diff --git a/concept-code/moduleVariables.vsm b/concept-code/moduleVariables.vsm
index 0610e63..e9a7cbe 100644
--- a/concept-code/moduleVariables.vsm
+++ b/concept-code/moduleVariables.vsm
@@ -1,4 +1,4 @@
-// test_output! [1, 2, 3, 12586269025]
+//! test_output([1, 2, 3, 12586269025])
 
 export @main {}
 
diff --git a/inputs/failing/exceptions/snapshotThis.ts b/inputs/failing/exceptions/snapshotThis.ts
index 01e6fcd..ef24858 100644
--- a/inputs/failing/exceptions/snapshotThis.ts
+++ b/inputs/failing/exceptions/snapshotThis.ts
@@ -1,4 +1,4 @@
-// test_output! 1
+//! test_output(1)
 // (Should be 0.)
 
 export default function main() {
diff --git a/inputs/failing/numberMethods/toExponentialInconsistent.ts b/inputs/failing/numberMethods/toExponentialInconsistent.ts
index ace15dc..c2c336e 100644
--- a/inputs/failing/numberMethods/toExponentialInconsistent.ts
+++ b/inputs/failing/numberMethods/toExponentialInconsistent.ts
@@ -1,4 +1,4 @@
-// test_output! [["1.20e+2","1.22e+2","1.22e+2","1.24e+2","1.24e+2"],["1.21e+0","1.22e+0","1.23e+0","1.24e+0","1.25e+0"]]
+//! test_output([["1.20e+2","1.22e+2","1.22e+2","1.24e+2","1.24e+2"],["1.21e+0","1.22e+0","1.23e+0","1.24e+0","1.25e+0"]])
 // This is wrong. There's some inconsistent banker's rounding going on.
 // It appears to be inherent to rust's {:.*e} formatting - a technical oversight?
 // Or maybe it has to do with parsing the source string into a number imprecisely?
diff --git a/inputs/passing/anonymousMain.ts b/inputs/passing/anonymousMain.ts
index 2f68310..648de58 100644
--- a/inputs/passing/anonymousMain.ts
+++ b/inputs/passing/anonymousMain.ts
@@ -1,4 +1,4 @@
-// test_output! "Done"
+//! test_output("Done")
 
 export default function () {
   return "Done";
diff --git a/inputs/passing/arrayBuiltin.ts b/inputs/passing/arrayBuiltin.ts
index 36b2695..6750cb2 100644
--- a/inputs/passing/arrayBuiltin.ts
+++ b/inputs/passing/arrayBuiltin.ts
@@ -1,4 +1,4 @@
-// test_output! [true,false,false,[1,2,3],["a","b","c"],[],[1,2,3],[],[,,],[3,1],[true]]
+//! test_output([true,false,false,[1,2,3],["a","b","c"],[],[1,2,3],[],[,,],[3,1],[true]])
 
 export default function () {
   return [
diff --git a/inputs/passing/assignmentEvalOrder.ts b/inputs/passing/assignmentEvalOrder.ts
index 204edca..67c54fb 100644
--- a/inputs/passing/assignmentEvalOrder.ts
+++ b/inputs/passing/assignmentEvalOrder.ts
@@ -1,4 +1,4 @@
-// test_output! {"left":"right"}
+//! test_output({"left":"right"})
 
 export default function main() {
   let x = {} as any;
diff --git a/inputs/passing/assignmentEvalOrder2.ts b/inputs/passing/assignmentEvalOrder2.ts
index 811b770..572f2f4 100644
--- a/inputs/passing/assignmentEvalOrder2.ts
+++ b/inputs/passing/assignmentEvalOrder2.ts
@@ -1,4 +1,4 @@
-// test_output! ["a","b"]
+//! test_output(["a","b"])
 
 export default function main() {
   let log = [];
diff --git a/inputs/passing/basicSymbol.ts b/inputs/passing/basicSymbol.ts
index 80feff7..bdfee56 100644
--- a/inputs/passing/basicSymbol.ts
+++ b/inputs/passing/basicSymbol.ts
@@ -1,4 +1,4 @@
-// test_output! [Symbol.iterator,{},3]
+//! test_output([Symbol.iterator,{},3])
 
 export default function main() {
   const x = { [Symbol.iterator]: 3 };
diff --git a/inputs/passing/bigint/noMix.ts b/inputs/passing/bigint/noMix.ts
index b76b5d8..8766764 100644
--- a/inputs/passing/bigint/noMix.ts
+++ b/inputs/passing/bigint/noMix.ts
@@ -1,4 +1,4 @@
-// test_output! E: TypeError{"message":"Cannot mix BigInt and other types"}
+//! test_output(E: TypeError{"message":"Cannot mix BigInt and other types"})
 
 export default function () {
   return 1 + (1n as unknown as number);
diff --git a/inputs/passing/binaryTree.ts b/inputs/passing/binaryTree.ts
index 8e50581..2bb767c 100644
--- a/inputs/passing/binaryTree.ts
+++ b/inputs/passing/binaryTree.ts
@@ -1,4 +1,4 @@
-// test_output! [[1,2,5],[1,2,3,4,5]]
+//! test_output([[1,2,5],[1,2,3,4,5]])
 
 export default function main() {
   let tree = BinaryTree();
diff --git a/inputs/passing/boolean.ts b/inputs/passing/boolean.ts
index 7203304..9806139 100644
--- a/inputs/passing/boolean.ts
+++ b/inputs/passing/boolean.ts
@@ -1,4 +1,4 @@
-// test_output! [true,false,false,true,true,true,true,false,true,false,false,false]
+//! test_output([true,false,false,true,true,true,true,false,true,false,false,false])
 
 export default function () {
   return [
diff --git a/inputs/passing/capture.ts b/inputs/passing/capture.ts
index 01b675c..5a60c83 100644
--- a/inputs/passing/capture.ts
+++ b/inputs/passing/capture.ts
@@ -1,4 +1,4 @@
-// test_output! [1,6,17]
+//! test_output([1,6,17])
 
 export default function () {
   const poly = buildPoly([1, 2, 3]); // 1 + 2*x + 3*x^2
diff --git a/inputs/passing/captureButNotRefBeforeInit.ts b/inputs/passing/captureButNotRefBeforeInit.ts
index cbcc815..62ea1f4 100644
--- a/inputs/passing/captureButNotRefBeforeInit.ts
+++ b/inputs/passing/captureButNotRefBeforeInit.ts
@@ -1,4 +1,4 @@
-// test_output! 3
+//! test_output(3)
 
 export default function main() {
   function foo() {
diff --git a/inputs/passing/captureShadowed.ts b/inputs/passing/captureShadowed.ts
index 21dabcd..d90028d 100644
--- a/inputs/passing/captureShadowed.ts
+++ b/inputs/passing/captureShadowed.ts
@@ -1,4 +1,4 @@
-// test_output! 7
+//! test_output(7)
 
 export default function main() {
   function foo() {
diff --git a/inputs/passing/complexPatternOrder.ts b/inputs/passing/complexPatternOrder.ts
index 2f08265..d165411 100644
--- a/inputs/passing/complexPatternOrder.ts
+++ b/inputs/passing/complexPatternOrder.ts
@@ -1,4 +1,4 @@
-// test_output! ["c","a","b"]
+//! test_output(["c","a","b"])
 
 export default function main() {
   let log = [];
diff --git a/inputs/passing/const/callNestedConstMethod.ts b/inputs/passing/const/callNestedConstMethod.ts
index 3f9a369..a205772 100644
--- a/inputs/passing/const/callNestedConstMethod.ts
+++ b/inputs/passing/const/callNestedConstMethod.ts
@@ -1,4 +1,4 @@
-// test_output! 37
+//! test_output(37)
 
 export default function () {
   const foo = new Foo();
diff --git a/inputs/passing/const/violateWithArrayPush.ts b/inputs/passing/const/violateWithArrayPush.ts
index 713f980..84f408e 100644
--- a/inputs/passing/const/violateWithArrayPush.ts
+++ b/inputs/passing/const/violateWithArrayPush.ts
@@ -1,4 +1,4 @@
-// test_output! E: TypeError{"message":"Cannot mutate this because it is const"}
+//! test_output(E: TypeError{"message":"Cannot mutate this because it is const"})
 
 export default function () {
   const arr = [1, 2];
diff --git a/inputs/passing/const/violateWithCustomMethod.ts b/inputs/passing/const/violateWithCustomMethod.ts
index 3fe5c69..46d58be 100644
--- a/inputs/passing/const/violateWithCustomMethod.ts
+++ b/inputs/passing/const/violateWithCustomMethod.ts
@@ -1,4 +1,4 @@
-// test_output! E: TypeError{"message":"Cannot mutate this because it is const"}
+//! test_output(E: TypeError{"message":"Cannot mutate this because it is const"})
 
 export default function () {
   const foo = new Foo();
diff --git a/inputs/passing/const/violateWithCustomMethodNested.ts b/inputs/passing/const/violateWithCustomMethodNested.ts
index 486c950..3dc1c7c 100644
--- a/inputs/passing/const/violateWithCustomMethodNested.ts
+++ b/inputs/passing/const/violateWithCustomMethodNested.ts
@@ -1,4 +1,4 @@
-// test_output! E: TypeError{"message":"Cannot mutate this because it is const"}
+//! test_output(E: TypeError{"message":"Cannot mutate this because it is const"})
 
 export default function () {
   const foo = new Foo();
diff --git a/inputs/passing/counter.ts b/inputs/passing/counter.ts
index 0ca2e92..9bdc0a6 100644
--- a/inputs/passing/counter.ts
+++ b/inputs/passing/counter.ts
@@ -1,4 +1,4 @@
-// test_output! [1,2,3]
+//! test_output([1,2,3])
 
 export default function main() {
   let c = Counter();
diff --git a/inputs/passing/customIterator.ts b/inputs/passing/customIterator.ts
index e91e2ec..6fb9d0b 100644
--- a/inputs/passing/customIterator.ts
+++ b/inputs/passing/customIterator.ts
@@ -1,4 +1,4 @@
-// test_output! [5,6,7,8,9]
+//! test_output([5,6,7,8,9])
 
 export default function () {
   let vals: number[] = [];
diff --git a/inputs/passing/destructuring/decl/array.ts b/inputs/passing/destructuring/decl/array.ts
index 50ed2e3..9e72981 100644
--- a/inputs/passing/destructuring/decl/array.ts
+++ b/inputs/passing/destructuring/decl/array.ts
@@ -1,4 +1,4 @@
-// test_output! 3
+//! test_output(3)
 
 export default function main() {
   const [a, b] = [1, 2];
diff --git a/inputs/passing/destructuring/decl/deeply_nested.ts b/inputs/passing/destructuring/decl/deeply_nested.ts
index a01c98e..d6b6e80 100644
--- a/inputs/passing/destructuring/decl/deeply_nested.ts
+++ b/inputs/passing/destructuring/decl/deeply_nested.ts
@@ -1,4 +1,4 @@
-// test_ouput! 42
+//! test_output(42)
 
 export default function main() {
   const [[[{ x: { y: [[{ z }]] } }]]] = [[[{ x: { y: [[{ z: 42 }]] } }]]];
diff --git a/inputs/passing/destructuring/decl/multi_complex.ts b/inputs/passing/destructuring/decl/multi_complex.ts
index 216c83e..9f57c7b 100644
--- a/inputs/passing/destructuring/decl/multi_complex.ts
+++ b/inputs/passing/destructuring/decl/multi_complex.ts
@@ -1,4 +1,4 @@
-// test_output! [55,145,237,43,31]
+//! test_output([55,145,237,43,31])
 
 export default function main() {
   let res = [];
diff --git a/inputs/passing/destructuring/decl/object.ts b/inputs/passing/destructuring/decl/object.ts
index 76d796c..f1b0d7d 100644
--- a/inputs/passing/destructuring/decl/object.ts
+++ b/inputs/passing/destructuring/decl/object.ts
@@ -1,4 +1,4 @@
-// test_output! 3
+//! test_output(3)
 
 export default function main() {
   const { a, b } = { a: 1, b: 2 };
diff --git a/inputs/passing/destructuring/param/array.ts b/inputs/passing/destructuring/param/array.ts
index 102506f..89efdb4 100644
--- a/inputs/passing/destructuring/param/array.ts
+++ b/inputs/passing/destructuring/param/array.ts
@@ -1,4 +1,4 @@
-// test_output! 3
+//! test_output(3)
 
 export default function main() {
   return foo([1, 2]);
diff --git a/inputs/passing/destructuring/param/deeply_nested.ts b/inputs/passing/destructuring/param/deeply_nested.ts
index 34f9006..c219416 100644
--- a/inputs/passing/destructuring/param/deeply_nested.ts
+++ b/inputs/passing/destructuring/param/deeply_nested.ts
@@ -1,4 +1,4 @@
-// test_ouput! 42
+//! test_output(42)
 
 export default function main() {
   return foo([[[{ x: { y: [[{ z: 42 }]] } }]]]);
diff --git a/inputs/passing/destructuring/param/multi_complex.ts b/inputs/passing/destructuring/param/multi_complex.ts
index 08d21b0..2cca171 100644
--- a/inputs/passing/destructuring/param/multi_complex.ts
+++ b/inputs/passing/destructuring/param/multi_complex.ts
@@ -1,4 +1,4 @@
-// test_output! [55,145,237,43,31]
+//! test_output([55,145,237,43,31])
 
 export default function main() {
   return [
diff --git a/inputs/passing/destructuring/param/object.ts b/inputs/passing/destructuring/param/object.ts
index e4624f0..a1782d8 100644
--- a/inputs/passing/destructuring/param/object.ts
+++ b/inputs/passing/destructuring/param/object.ts
@@ -1,4 +1,4 @@
-// test_output! 3
+//! test_output(3)
 
 export default function main() {
   return foo({ a: 1, b: 2 });
diff --git a/inputs/passing/dontRevertMath.ts b/inputs/passing/dontRevertMath.ts
index 786f7c4..d4eda12 100644
--- a/inputs/passing/dontRevertMath.ts
+++ b/inputs/passing/dontRevertMath.ts
@@ -1,4 +1,4 @@
-// test_output! undefined
+//! test_output(undefined)
 
 export default function () {
   try {
diff --git a/inputs/passing/doublePreInc.ts b/inputs/passing/doublePreInc.ts
index c8d66d0..3b47345 100644
--- a/inputs/passing/doublePreInc.ts
+++ b/inputs/passing/doublePreInc.ts
@@ -1,4 +1,4 @@
-// test_output! 3
+//! test_output(3)
 
 export default function main() {
   let x = 0;
diff --git a/inputs/passing/exceptions/catchDestructure.ts b/inputs/passing/exceptions/catchDestructure.ts
index ac4f09d..0aea903 100644
--- a/inputs/passing/exceptions/catchDestructure.ts
+++ b/inputs/passing/exceptions/catchDestructure.ts
@@ -1,4 +1,4 @@
-// test_output! 8
+//! test_output(8)
 
 export default function () {
   try {
diff --git a/inputs/passing/exceptions/catchNonLocal.ts b/inputs/passing/exceptions/catchNonLocal.ts
index bdaf3b9..127b888 100644
--- a/inputs/passing/exceptions/catchNonLocal.ts
+++ b/inputs/passing/exceptions/catchNonLocal.ts
@@ -1,4 +1,4 @@
-// test_output!: "Caught: boom"
+//! test_output("Caught: boom")
 
 export default function () {
   try {
diff --git a/inputs/passing/exceptions/finallyBreakSwallowsException.ts b/inputs/passing/exceptions/finallyBreakSwallowsException.ts
index a4d3261..3356f13 100644
--- a/inputs/passing/exceptions/finallyBreakSwallowsException.ts
+++ b/inputs/passing/exceptions/finallyBreakSwallowsException.ts
@@ -1,4 +1,4 @@
-// test_output! "🤷‍♂️"
+//! test_output("🤷‍♂️")
 
 export default function () {
   while (true) {
diff --git a/inputs/passing/exceptions/finallyBreakSwallowsReturn.ts b/inputs/passing/exceptions/finallyBreakSwallowsReturn.ts
index 0e0bd08..3d23dc4 100644
--- a/inputs/passing/exceptions/finallyBreakSwallowsReturn.ts
+++ b/inputs/passing/exceptions/finallyBreakSwallowsReturn.ts
@@ -1,4 +1,4 @@
-// test_output! "that thing"
+//! test_output("that thing")
 
 export default function () {
   while (true) {
diff --git a/inputs/passing/exceptions/finallyReturnSwallowsException.ts b/inputs/passing/exceptions/finallyReturnSwallowsException.ts
index 26ccd6b..0e00d02 100644
--- a/inputs/passing/exceptions/finallyReturnSwallowsException.ts
+++ b/inputs/passing/exceptions/finallyReturnSwallowsException.ts
@@ -1,4 +1,4 @@
-// test_output! 42
+//! test_output(42)
 
 export default function () {
   try {
diff --git a/inputs/passing/exceptions/finallyWithoutThrow.ts b/inputs/passing/exceptions/finallyWithoutThrow.ts
index 467780c..f20ea30 100644
--- a/inputs/passing/exceptions/finallyWithoutThrow.ts
+++ b/inputs/passing/exceptions/finallyWithoutThrow.ts
@@ -1,4 +1,4 @@
-// test_output! "Ok"
+//! test_output("Ok")
 
 export default function () {
   let result: string;
diff --git a/inputs/passing/exceptions/isReturningReset.ts b/inputs/passing/exceptions/isReturningReset.ts
index a3e4ccd..ca4452e 100644
--- a/inputs/passing/exceptions/isReturningReset.ts
+++ b/inputs/passing/exceptions/isReturningReset.ts
@@ -1,4 +1,4 @@
-// test_output! "that thing"
+//! test_output("that thing")
 
 export default function () {
   while (true) {
diff --git a/inputs/passing/exceptions/nestedFinally.ts b/inputs/passing/exceptions/nestedFinally.ts
index 6f7810e..24b3ddb 100644
--- a/inputs/passing/exceptions/nestedFinally.ts
+++ b/inputs/passing/exceptions/nestedFinally.ts
@@ -1,4 +1,4 @@
-// test_error! ["outer finally",Error{"message":"inner finally"}]
+//! test_error(["outer finally",Error{"message":"inner finally"}])
 
 export default function () {
   let logs: unknown[] = [];
diff --git a/inputs/passing/exceptions/nestedFinallyReturn.ts b/inputs/passing/exceptions/nestedFinallyReturn.ts
index b710e50..903beb9 100644
--- a/inputs/passing/exceptions/nestedFinallyReturn.ts
+++ b/inputs/passing/exceptions/nestedFinallyReturn.ts
@@ -1,4 +1,4 @@
-// test_output! "this thing"
+//! test_output("this thing")
 
 export default function () {
   while (true) {
diff --git a/inputs/passing/exceptions/nestedRethrow.ts b/inputs/passing/exceptions/nestedRethrow.ts
index 6c83caf..a2d4c57 100644
--- a/inputs/passing/exceptions/nestedRethrow.ts
+++ b/inputs/passing/exceptions/nestedRethrow.ts
@@ -1,4 +1,4 @@
-// test_error! Error{"message":"nested error"}
+//! test_error(Error{"message":"nested error"})
 
 export default function () {
   try {
diff --git a/inputs/passing/exceptions/nestedTry.ts b/inputs/passing/exceptions/nestedTry.ts
index a23b728..899169c 100644
--- a/inputs/passing/exceptions/nestedTry.ts
+++ b/inputs/passing/exceptions/nestedTry.ts
@@ -1,4 +1,4 @@
-// test_output! ["boom"]
+//! test_output(["boom"])
 //
 // Note: the original intention was for this to output ["here","nested boom","boom"] to check where
 // the control flow goes. This worked at the time, but now that snapshotting variables that can be
diff --git a/inputs/passing/exceptions/revertMethodCallOnCatch.ts b/inputs/passing/exceptions/revertMethodCallOnCatch.ts
index 8fbf422..8cfae66 100644
--- a/inputs/passing/exceptions/revertMethodCallOnCatch.ts
+++ b/inputs/passing/exceptions/revertMethodCallOnCatch.ts
@@ -1,4 +1,4 @@
-// test_output! [[],["item"]]
+//! test_output([[],["item"]])
 
 export default function () {
   return [
diff --git a/inputs/passing/exceptions/revertOnCatch.ts b/inputs/passing/exceptions/revertOnCatch.ts
index bdf885e..9948c01 100644
--- a/inputs/passing/exceptions/revertOnCatch.ts
+++ b/inputs/passing/exceptions/revertOnCatch.ts
@@ -1,4 +1,4 @@
-// test_output! [0,1]
+//! test_output([0,1])
 
 export default function () {
   return [
diff --git a/inputs/passing/exceptions/revertSmallQueue.ts b/inputs/passing/exceptions/revertSmallQueue.ts
index f2a22cd..5fe939d 100644
--- a/inputs/passing/exceptions/revertSmallQueue.ts
+++ b/inputs/passing/exceptions/revertSmallQueue.ts
@@ -1,4 +1,4 @@
-// test_output! [1,3,"SmallQueue is already full"]
+//! test_output([1,3,"SmallQueue is already full"])
 
 export default function () {
   let a = new SmallQueue(["item1"]);
diff --git a/inputs/passing/exceptions/throwCustomError.ts b/inputs/passing/exceptions/throwCustomError.ts
index 7eb280b..0800cb0 100644
--- a/inputs/passing/exceptions/throwCustomError.ts
+++ b/inputs/passing/exceptions/throwCustomError.ts
@@ -1,4 +1,4 @@
-// test_error! E: {"code":"400","message":"Bad request"}
+//! test_error(E: {"code":"400","message":"Bad request"})
 
 export default function () {
   throw new CustomError(400, "Bad request");
diff --git a/inputs/passing/exceptions/throwError.ts b/inputs/passing/exceptions/throwError.ts
index d54ef40..c3a6188 100644
--- a/inputs/passing/exceptions/throwError.ts
+++ b/inputs/passing/exceptions/throwError.ts
@@ -1,4 +1,4 @@
-// test_error! Error{"message":"Test error"}
+//! test_error(Error{"message":"Test error"})
 
 export default function () {
   throw new Error("Test error");
diff --git a/inputs/passing/exceptions/throwTypeError.ts b/inputs/passing/exceptions/throwTypeError.ts
index e5eb35a..5d84ebf 100644
--- a/inputs/passing/exceptions/throwTypeError.ts
+++ b/inputs/passing/exceptions/throwTypeError.ts
@@ -1,4 +1,4 @@
-// test_error! E: TypeError{"message":"Cannot subscript undefined"}
+//! test_error(E: TypeError{"message":"Cannot subscript undefined"})
 
 export default function () {
   const arr = undefined;
diff --git a/inputs/passing/exceptions/tryCatch.ts b/inputs/passing/exceptions/tryCatch.ts
index 8ded5b6..64a2fa9 100644
--- a/inputs/passing/exceptions/tryCatch.ts
+++ b/inputs/passing/exceptions/tryCatch.ts
@@ -1,4 +1,4 @@
-// test_output! Error{"message":"Something went wrong"}
+//! test_output(Error{"message":"Something went wrong"})
 
 export default function () {
   try {
diff --git a/inputs/passing/exceptions/tryCatchFinally.ts b/inputs/passing/exceptions/tryCatchFinally.ts
index 57f38fb..1561110 100644
--- a/inputs/passing/exceptions/tryCatchFinally.ts
+++ b/inputs/passing/exceptions/tryCatchFinally.ts
@@ -1,4 +1,4 @@
-// test_output! E: Error{"message":"teraboom"}
+//! test_output(E: Error{"message":"teraboom"})
 
 export default function () {
   try {
diff --git a/inputs/passing/exceptions/tryCatchRethrow.ts b/inputs/passing/exceptions/tryCatchRethrow.ts
index 30324fc..c312401 100644
--- a/inputs/passing/exceptions/tryCatchRethrow.ts
+++ b/inputs/passing/exceptions/tryCatchRethrow.ts
@@ -1,4 +1,4 @@
-// test_error! E: ["rethrow",Error{"message":"Something went wrong"}]
+//! test_error(E: ["rethrow",Error{"message":"Something went wrong"}])
 
 export default function () {
   try {
diff --git a/inputs/passing/exceptions/tryFinally.ts b/inputs/passing/exceptions/tryFinally.ts
index 904d14d..fcdc469 100644
--- a/inputs/passing/exceptions/tryFinally.ts
+++ b/inputs/passing/exceptions/tryFinally.ts
@@ -1,4 +1,4 @@
-// test_output! E: Error{"message":"Something went wrong"}
+//! test_output(E: Error{"message":"Something went wrong"})
 
 export default function () {
   try {
diff --git a/inputs/passing/exceptions/tryReturnFinallyReturn.ts b/inputs/passing/exceptions/tryReturnFinallyReturn.ts
index fe6ba65..47d0d2d 100644
--- a/inputs/passing/exceptions/tryReturnFinallyReturn.ts
+++ b/inputs/passing/exceptions/tryReturnFinallyReturn.ts
@@ -1,4 +1,4 @@
-// test_output! 42
+//! test_output(42)
 
 export default function () {
   try {
diff --git a/inputs/passing/forOf.ts b/inputs/passing/forOf.ts
index 0b19018..faf9620 100644
--- a/inputs/passing/forOf.ts
+++ b/inputs/passing/forOf.ts
@@ -1,4 +1,4 @@
-// test_output! [1,4,9]
+//! test_output([1,4,9])
 
 export default function () {
   let vals: number[] = [];
diff --git a/inputs/passing/hello.ts b/inputs/passing/hello.ts
index 2ea996c..d2d1c45 100644
--- a/inputs/passing/hello.ts
+++ b/inputs/passing/hello.ts
@@ -1,4 +1,4 @@
-// test_output! "Hello world!"
+//! test_output("Hello world!")
 
 export default function main() {
   return 'Hello world!';
diff --git a/inputs/passing/importBar.ts b/inputs/passing/importBar.ts
index 2abfcb2..202d0ab 100644
--- a/inputs/passing/importBar.ts
+++ b/inputs/passing/importBar.ts
@@ -1,4 +1,4 @@
-// test_output! ["this is the bar function","this is the bar function"]
+//! test_output(["this is the bar function","this is the bar function"])
 
 import { bar, barExported } from "./helpers/bar.ts";
 
diff --git a/inputs/passing/importFoo.ts b/inputs/passing/importFoo.ts
index 234d4c1..47ebc97 100644
--- a/inputs/passing/importFoo.ts
+++ b/inputs/passing/importFoo.ts
@@ -1,4 +1,4 @@
-// test_output! "this is the foo function"
+//! test_output("this is the foo function")
 
 import foo from "./helpers/foo.ts";
 
diff --git a/inputs/passing/importFooAndBar.ts b/inputs/passing/importFooAndBar.ts
index bbee094..c899369 100644
--- a/inputs/passing/importFooAndBar.ts
+++ b/inputs/passing/importFooAndBar.ts
@@ -1,4 +1,4 @@
-// test_output! ["this is the foo function","this is the bar function"]
+//! test_output(["this is the foo function","this is the bar function"])
 
 import { bar, foo } from "./helpers/fooAndBar.ts";
 
diff --git a/inputs/passing/importFoobar.ts b/inputs/passing/importFoobar.ts
index 8ec446a..822167c 100644
--- a/inputs/passing/importFoobar.ts
+++ b/inputs/passing/importFoobar.ts
@@ -1,4 +1,4 @@
-// test_output! ["this is the foo function","this is the bar function"]
+//! test_output(["this is the foo function","this is the bar function"])
 
 import foobar from "./helpers/foobar.ts";
 
diff --git a/inputs/passing/importType.ts b/inputs/passing/importType.ts
index 7527d93..6103446 100644
--- a/inputs/passing/importType.ts
+++ b/inputs/passing/importType.ts
@@ -1,4 +1,4 @@
-// test_output! "done"
+//! test_output("done")
 
 import { type Type } from "./helpers/Type.ts";
 
diff --git a/inputs/passing/iteration/manualArrayIteration.ts b/inputs/passing/iteration/manualArrayIteration.ts
index e256fd8..5a5ca97 100644
--- a/inputs/passing/iteration/manualArrayIteration.ts
+++ b/inputs/passing/iteration/manualArrayIteration.ts
@@ -1,4 +1,4 @@
-// test_output! [[1,false],[2,false],[3,false],[undefined,true],[undefined,true]]
+//! test_output([[1,false],[2,false],[3,false],[undefined,true],[undefined,true]])
 
 export default function () {
   const vals = [1, 2, 3];
diff --git a/inputs/passing/mergeSort.ts b/inputs/passing/mergeSort.ts
index 9377515..e3a284a 100644
--- a/inputs/passing/mergeSort.ts
+++ b/inputs/passing/mergeSort.ts
@@ -1,4 +1,4 @@
-// test_output! [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18]
+//! test_output([1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18])
 
 export default function main() {
   const x = [7, 18, 9, 11, 16, 3, 8, 2, 5, 4, 6, 14, 15, 17, 10, 12, 1, 13];
diff --git a/inputs/passing/mergeSortStepper.ts b/inputs/passing/mergeSortStepper.ts
index aaeff13..af6577d 100644
--- a/inputs/passing/mergeSortStepper.ts
+++ b/inputs/passing/mergeSortStepper.ts
@@ -1,4 +1,4 @@
-// test_output (TODO broken!) [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18]
+// test_output((TODO broken!) [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18])
 
 declare const Debug: {
   log: (...args: unknown[]) => undefined;
diff --git a/inputs/passing/multiAssignment.ts b/inputs/passing/multiAssignment.ts
index 4d4916d..910a22c 100644
--- a/inputs/passing/multiAssignment.ts
+++ b/inputs/passing/multiAssignment.ts
@@ -1,4 +1,4 @@
-// test_output! [1,1]
+//! test_output([1,1])
 
 export default function main() {
   let a;
diff --git a/inputs/passing/multiCompoundAssignment.ts b/inputs/passing/multiCompoundAssignment.ts
index 223d238..8c58c39 100644
--- a/inputs/passing/multiCompoundAssignment.ts
+++ b/inputs/passing/multiCompoundAssignment.ts
@@ -1,4 +1,4 @@
-// test_output! [17,15,12]
+//! test_output([17,15,12])
 
 export default function main() {
   let a = 2;
diff --git a/inputs/passing/mutatedRegisterIssue.ts b/inputs/passing/mutatedRegisterIssue.ts
index d7516c4..00357a8 100644
--- a/inputs/passing/mutatedRegisterIssue.ts
+++ b/inputs/passing/mutatedRegisterIssue.ts
@@ -1,4 +1,4 @@
-// test_output! [[1,2,3,4],[4,3,2,1]]
+//! test_output([[1,2,3,4],[4,3,2,1]])
 
 export default function main() {
   let x = [1, 2, 3, 4];
diff --git a/inputs/passing/nestedAssignment.ts b/inputs/passing/nestedAssignment.ts
index 165e577..c366727 100644
--- a/inputs/passing/nestedAssignment.ts
+++ b/inputs/passing/nestedAssignment.ts
@@ -1,4 +1,4 @@
-// test_output! [1,4,9]
+//! test_output([1,4,9])
 
 export default function main() {
   let x = 0;
diff --git a/inputs/passing/nestedCompoundAssignment.ts b/inputs/passing/nestedCompoundAssignment.ts
index 38f2b66..846994d 100644
--- a/inputs/passing/nestedCompoundAssignment.ts
+++ b/inputs/passing/nestedCompoundAssignment.ts
@@ -1,4 +1,4 @@
-// test_output! [1,5,14]
+//! test_output([1,5,14])
 
 export default function main() {
   let x = 0;
diff --git a/inputs/passing/nestedFn.ts b/inputs/passing/nestedFn.ts
index ff6a388..1532ad6 100644
--- a/inputs/passing/nestedFn.ts
+++ b/inputs/passing/nestedFn.ts
@@ -1,4 +1,4 @@
-// test_output! 3
+//! test_output(3)
 
 export default function () {
   function foo() {
diff --git a/inputs/passing/nestedFnCapture.ts b/inputs/passing/nestedFnCapture.ts
index 9eb0cd9..a650e7e 100644
--- a/inputs/passing/nestedFnCapture.ts
+++ b/inputs/passing/nestedFnCapture.ts
@@ -1,4 +1,4 @@
-// test_output! 3
+//! test_output(3)
 
 export default function () {
   const x = 3;
diff --git a/inputs/passing/numberMethods/isInteger.ts b/inputs/passing/numberMethods/isInteger.ts
index abd6f68..eda6e7f 100644
--- a/inputs/passing/numberMethods/isInteger.ts
+++ b/inputs/passing/numberMethods/isInteger.ts
@@ -1,4 +1,4 @@
-// test_output! [[true,true,true,true,true,true,true],[false,false,false,false,false]]
+//! test_output([[true,true,true,true,true,true,true],[false,false,false,false,false]])
 
 export default function () {
   const integers = [
diff --git a/inputs/passing/numberMethods/isSafeInteger.ts b/inputs/passing/numberMethods/isSafeInteger.ts
index 2b27349..c692377 100644
--- a/inputs/passing/numberMethods/isSafeInteger.ts
+++ b/inputs/passing/numberMethods/isSafeInteger.ts
@@ -1,4 +1,4 @@
-// test_output! [[true,true,true,true,true,true],[false,false,false,false,false,false]]
+//! test_output([[true,true,true,true,true,true],[false,false,false,false,false,false]])
 
 export default function () {
   const minSafe = -9007199254740991;
diff --git a/inputs/passing/numberMethods/parseFloat.ts b/inputs/passing/numberMethods/parseFloat.ts
index 9469a5e..dab4373 100644
--- a/inputs/passing/numberMethods/parseFloat.ts
+++ b/inputs/passing/numberMethods/parseFloat.ts
@@ -1,4 +1,4 @@
-// test_output! [[37,-37,37.1,37,37.1,1.5,0.1,1.23],[NaN]]
+//! test_output([[37,-37,37.1,37,37.1,1.5,0.1,1.23],[NaN]])
 
 export default function () {
   const numbers = [
diff --git a/inputs/passing/numberMethods/parseInt.ts b/inputs/passing/numberMethods/parseInt.ts
index 359406e..915812c 100644
--- a/inputs/passing/numberMethods/parseInt.ts
+++ b/inputs/passing/numberMethods/parseInt.ts
@@ -1,4 +1,4 @@
-// test_output! [[37,-37,15,37,37,31],[NaN,NaN]]
+//! test_output([[37,-37,15,37,37,31],[NaN,NaN]])
 
 export default function () {
   const positive_and_negative = [
diff --git a/inputs/passing/numberMethods/toExponential.ts b/inputs/passing/numberMethods/toExponential.ts
index 1ed610c..2bbe6b7 100644
--- a/inputs/passing/numberMethods/toExponential.ts
+++ b/inputs/passing/numberMethods/toExponential.ts
@@ -1,4 +1,4 @@
-// test_output! [["0e+0","1.2e+0","1.2e+1","1.2e+2","1.2e-1","1.2e-2","1.2e-3","1.2e-4"],["0.00e+0","1.23e+0","1.23e+1","1.23e-1","1.23e-2","1.23e-3","1.23e-4"],["NaN","Infinity"]]
+//! test_output([["0e+0","1.2e+0","1.2e+1","1.2e+2","1.2e-1","1.2e-2","1.2e-3","1.2e-4"],["0.00e+0","1.23e+0","1.23e+1","1.23e-1","1.23e-2","1.23e-3","1.23e-4"],["NaN","Infinity"]])
 
 export default function () {
   const withoutPrecision = [
diff --git a/inputs/passing/numberMethods/toFixed.ts b/inputs/passing/numberMethods/toFixed.ts
index c61f17f..947a583 100644
--- a/inputs/passing/numberMethods/toFixed.ts
+++ b/inputs/passing/numberMethods/toFixed.ts
@@ -1,4 +1,4 @@
-// test_output! [["0.00","1.23","123.00","0.01","0.00123","12345.68","3.14","-1.00"],["NaN","Infinity"]]
+//! test_output([["0.00","1.23","123.00","0.01","0.00123","12345.68","3.14","-1.00"],["NaN","Infinity"]])
 
 export default function () {
   const positive = [
diff --git a/inputs/passing/patternEvalOrder.ts b/inputs/passing/patternEvalOrder.ts
index 8c0acb0..8550dc7 100644
--- a/inputs/passing/patternEvalOrder.ts
+++ b/inputs/passing/patternEvalOrder.ts
@@ -1,4 +1,4 @@
-// test_output! "right"
+//! test_output("right")
 
 export default function main() {
   let x;
diff --git a/inputs/passing/patternEvalOrder2.ts b/inputs/passing/patternEvalOrder2.ts
index febdfb3..32428d4 100644
--- a/inputs/passing/patternEvalOrder2.ts
+++ b/inputs/passing/patternEvalOrder2.ts
@@ -1,4 +1,4 @@
-// test_output! ["c","a","b"]
+//! test_output(["c","a","b"])
 
 export default function main() {
   let log: string[] = [];
diff --git a/inputs/passing/preincrement.ts b/inputs/passing/preincrement.ts
index d3bfc78..939eb53 100644
--- a/inputs/passing/preincrement.ts
+++ b/inputs/passing/preincrement.ts
@@ -1,4 +1,4 @@
-// test_output! 2
+//! test_output(2)
 
 export default function main() {
   let value = 1;
diff --git a/inputs/passing/projEuler/p1.ts b/inputs/passing/projEuler/p1.ts
index 2427078..e35f9e9 100644
--- a/inputs/passing/projEuler/p1.ts
+++ b/inputs/passing/projEuler/p1.ts
@@ -1,4 +1,4 @@
-// test_output! 233168
+//! test_output(233168)
 
 export default function main() {
   let sum = 0;
diff --git a/inputs/passing/projEuler/p11.ts b/inputs/passing/projEuler/p11.ts
index 84cafa8..6abb831 100644
--- a/inputs/passing/projEuler/p11.ts
+++ b/inputs/passing/projEuler/p11.ts
@@ -1,4 +1,4 @@
-// test_output! 70600674
+//! test_output(70600674)
 
 export default function main() {
   const grid = [
diff --git a/inputs/passing/projEuler/p13.ts b/inputs/passing/projEuler/p13.ts
index d25915e..0a441a8 100644
--- a/inputs/passing/projEuler/p13.ts
+++ b/inputs/passing/projEuler/p13.ts
@@ -1,4 +1,4 @@
-// test_output! "Probably 5537376230 (trailing digits: 39036)"
+//! test_output("Probably 5537376230 (trailing digits: 39036)")
 
 export default function main() {
   const numStrs = [
diff --git a/inputs/passing/projEuler/p15.ts b/inputs/passing/projEuler/p15.ts
index 5ddc773..413db40 100644
--- a/inputs/passing/projEuler/p15.ts
+++ b/inputs/passing/projEuler/p15.ts
@@ -1,4 +1,4 @@
-// test_output! 137846528820
+//! test_output(137846528820)
 
 export default function main() {
   let rc = new RouteCalculator();
diff --git a/inputs/passing/projEuler/p16.ts b/inputs/passing/projEuler/p16.ts
index 7a96621..3e7584e 100644
--- a/inputs/passing/projEuler/p16.ts
+++ b/inputs/passing/projEuler/p16.ts
@@ -1,4 +1,4 @@
-// test_output! 1366
+//! test_output(1366)
 
 import plus from "./helpers/plus.ts";
 
diff --git a/inputs/passing/projEuler/p18.ts b/inputs/passing/projEuler/p18.ts
index 074bc1f..c9034f4 100644
--- a/inputs/passing/projEuler/p18.ts
+++ b/inputs/passing/projEuler/p18.ts
@@ -1,4 +1,4 @@
-// test_output! 1074
+//! test_output(1074)
 
 export default function main() {
   let tower = [
diff --git a/inputs/passing/projEuler/p19.ts b/inputs/passing/projEuler/p19.ts
index 09737ee..260bdbf 100644
--- a/inputs/passing/projEuler/p19.ts
+++ b/inputs/passing/projEuler/p19.ts
@@ -1,4 +1,4 @@
-// test_output! 171
+//! test_output(171)
 
 declare const Debug: {
   log: (...args: unknown[]) => undefined;
diff --git a/inputs/passing/projEuler/p2.ts b/inputs/passing/projEuler/p2.ts
index a276708..2ba4a0d 100644
--- a/inputs/passing/projEuler/p2.ts
+++ b/inputs/passing/projEuler/p2.ts
@@ -1,4 +1,4 @@
-// test_output! 4613732
+//! test_output(4613732)
 
 export default function main() {
   let sum = 0;
diff --git a/inputs/passing/projEuler/p25.ts b/inputs/passing/projEuler/p25.ts
index 195d95b..57123ca 100644
--- a/inputs/passing/projEuler/p25.ts
+++ b/inputs/passing/projEuler/p25.ts
@@ -1,4 +1,4 @@
-// test_output! 4782
+//! test_output(4782)
 
 export default function main() {
   let fibLast = 1n;
diff --git a/inputs/passing/projEuler/p3.ts b/inputs/passing/projEuler/p3.ts
index 0e4ec76..f77e13b 100644
--- a/inputs/passing/projEuler/p3.ts
+++ b/inputs/passing/projEuler/p3.ts
@@ -1,4 +1,4 @@
-// test_output! [71,839,1471,6857]
+//! test_output([71,839,1471,6857])
 
 import { factorize } from "./helpers/primes.ts";
 
diff --git a/inputs/passing/projEuler/p4.ts b/inputs/passing/projEuler/p4.ts
index cb449a0..1eed61f 100644
--- a/inputs/passing/projEuler/p4.ts
+++ b/inputs/passing/projEuler/p4.ts
@@ -1,4 +1,4 @@
-// test_output! 906609
+//! test_output(906609)
 
 export default function main() {
   let largest = 0;
diff --git a/inputs/passing/projEuler/p5.ts b/inputs/passing/projEuler/p5.ts
index 5cf0a4b..cd9fe44 100644
--- a/inputs/passing/projEuler/p5.ts
+++ b/inputs/passing/projEuler/p5.ts
@@ -1,4 +1,4 @@
-// test_output! 232792560
+//! test_output(232792560)
 
 import { factorize } from "./helpers/primes.ts";
 
diff --git a/inputs/passing/projEuler/p6.ts b/inputs/passing/projEuler/p6.ts
index bf9095c..ff01d99 100644
--- a/inputs/passing/projEuler/p6.ts
+++ b/inputs/passing/projEuler/p6.ts
@@ -1,4 +1,4 @@
-// test_output! 25164150
+//! test_output(25164150)
 
 export default function main() {
   return squareOfSum(100) - sumOfSquares(100);
diff --git a/inputs/passing/projEuler/p8.ts b/inputs/passing/projEuler/p8.ts
index 3e01b67..abacea9 100644
--- a/inputs/passing/projEuler/p8.ts
+++ b/inputs/passing/projEuler/p8.ts
@@ -1,4 +1,4 @@
-// test_output! 23514624000
+//! test_output(23514624000)
 
 export default function main() {
   const digits = [
diff --git a/inputs/passing/projEuler/p9.ts b/inputs/passing/projEuler/p9.ts
index 03ac0d6..c003f52 100644
--- a/inputs/passing/projEuler/p9.ts
+++ b/inputs/passing/projEuler/p9.ts
@@ -1,4 +1,4 @@
-// test_output! 31875000
+//! test_output(31875000)
 
 export default function main() {
   for (let a = 1; a <= 1000; a++) {
diff --git a/inputs/passing/readme-demo.ts b/inputs/passing/readme-demo.ts
index fe960dc..bc03a02 100644
--- a/inputs/passing/readme-demo.ts
+++ b/inputs/passing/readme-demo.ts
@@ -1,4 +1,4 @@
-// test_output! false
+//! test_output(false)
 
 export default function main() {
   const leftBowl = ["apple", "mango"];
diff --git a/inputs/passing/recursiveCapture.ts b/inputs/passing/recursiveCapture.ts
index e4bfe55..c1bf5e9 100644
--- a/inputs/passing/recursiveCapture.ts
+++ b/inputs/passing/recursiveCapture.ts
@@ -1,4 +1,4 @@
-// test_output! 120
+//! test_output(120)
 
 export default function main() {
   const one = 1;
diff --git a/inputs/passing/shadow.ts b/inputs/passing/shadow.ts
index 992a9cb..ebd14bf 100644
--- a/inputs/passing/shadow.ts
+++ b/inputs/passing/shadow.ts
@@ -1,4 +1,4 @@
-// test_output! 3
+//! test_output(3)
 
 export default function main() {
   let sum = 0;
diff --git a/inputs/passing/spread.ts b/inputs/passing/spread.ts
index c634757..7678a64 100644
--- a/inputs/passing/spread.ts
+++ b/inputs/passing/spread.ts
@@ -1,4 +1,4 @@
-// test_output! [".abc.",".abc.",".abc.",".abc."]
+//! test_output([".abc.",".abc.",".abc.",".abc."])
 
 export default function () {
   const middle = ["a", "b", "c"] as const;
diff --git a/inputs/passing/spreadAndReturn.ts b/inputs/passing/spreadAndReturn.ts
index 9c8fe57..3533690 100644
--- a/inputs/passing/spreadAndReturn.ts
+++ b/inputs/passing/spreadAndReturn.ts
@@ -1,4 +1,4 @@
-// // test_output! {}
+// //! test_output({})
 
 export default function () {
   let x = new X();
diff --git a/inputs/passing/stringIndexing.ts b/inputs/passing/stringIndexing.ts
index cc80bce..51ac399 100644
--- a/inputs/passing/stringIndexing.ts
+++ b/inputs/passing/stringIndexing.ts
@@ -1,4 +1,4 @@
-// test_output! [undefined,"🚀","","","","🍹","","","","a","b","c","£","","한","","","🎨","","","",undefined]
+//! test_output([undefined,"🚀","","","","🍹","","","","a","b","c","£","","한","","","🎨","","","",undefined])
 
 export default function () {
   const str = "🚀🍹abc£한🎨";
diff --git a/inputs/passing/stringIteration.ts b/inputs/passing/stringIteration.ts
index f5f919e..05510be 100644
--- a/inputs/passing/stringIteration.ts
+++ b/inputs/passing/stringIteration.ts
@@ -1,4 +1,4 @@
-// test_output! ["🚀","🍹","a","b","c","£","한","🎨"]
+//! test_output(["🚀","🍹","a","b","c","£","한","🎨"])
 
 export default function () {
   const str = "🚀🍹abc£한🎨";
diff --git a/inputs/passing/stringMethods/at.ts b/inputs/passing/stringMethods/at.ts
index e75693c..b118619 100644
--- a/inputs/passing/stringMethods/at.ts
+++ b/inputs/passing/stringMethods/at.ts
@@ -1,4 +1,4 @@
-// test_output! "r"
+//! test_output("r")
 
 export default function() {
   return "foobar".at(-1);
diff --git a/inputs/passing/stringMethods/codePointAt.ts b/inputs/passing/stringMethods/codePointAt.ts
index a323236..e2a43a0 100644
--- a/inputs/passing/stringMethods/codePointAt.ts
+++ b/inputs/passing/stringMethods/codePointAt.ts
@@ -1,4 +1,4 @@
-// test_output! [128640,undefined,undefined,undefined,127865,undefined,undefined,undefined,97,98,99,163,undefined,54620,undefined,undefined,127912,undefined,undefined,undefined]
+//! test_output([128640,undefined,undefined,undefined,127865,undefined,undefined,undefined,97,98,99,163,undefined,54620,undefined,undefined,127912,undefined,undefined,undefined])
 
 // ValueScript uses utf8, so it deviates from JavaScript's utf16.
 // We're also not really doing the utf8 equivalent of JavaScript's utf16 either.
diff --git a/inputs/passing/stringMethods/endsWith.ts b/inputs/passing/stringMethods/endsWith.ts
index 56111ac..b0a07ae 100644
--- a/inputs/passing/stringMethods/endsWith.ts
+++ b/inputs/passing/stringMethods/endsWith.ts
@@ -1,4 +1,4 @@
-// test_output! [true,false,true,true,true,true,false,true,true,false]
+//! test_output([true,false,true,true,true,true,false,true,true,false])
 
 export default function () {
   return [
diff --git a/inputs/passing/stringMethods/fromCodePoint.ts b/inputs/passing/stringMethods/fromCodePoint.ts
index 717bf5c..35acb9a 100644
--- a/inputs/passing/stringMethods/fromCodePoint.ts
+++ b/inputs/passing/stringMethods/fromCodePoint.ts
@@ -1,4 +1,4 @@
-// test_output! "Hi 👋"
+//! test_output("Hi 👋")
 
 export default function () {
   return String.fromCodePoint(72, 105, 32, 128075);
diff --git a/inputs/passing/stringMethods/includes.ts b/inputs/passing/stringMethods/includes.ts
index 7e842ea..2a2605c 100644
--- a/inputs/passing/stringMethods/includes.ts
+++ b/inputs/passing/stringMethods/includes.ts
@@ -1,4 +1,4 @@
-// test_output! [[true,true,true,true,true,true],[false,false,false,false]]
+//! test_output([[true,true,true,true,true,true],[false,false,false,false]])
 
 export default function () {
   const positive = [
diff --git a/inputs/passing/stringMethods/indexOf.ts b/inputs/passing/stringMethods/indexOf.ts
index 9ee64d6..23208d5 100644
--- a/inputs/passing/stringMethods/indexOf.ts
+++ b/inputs/passing/stringMethods/indexOf.ts
@@ -1,4 +1,4 @@
-// test_output! [[0,3,1,0,0,3],[-1,-1,-1,-1]]
+//! test_output([[0,3,1,0,0,3],[-1,-1,-1,-1]])
 
 export default function () {
   const positive = [
diff --git a/inputs/passing/stringMethods/lastIndexOf.ts b/inputs/passing/stringMethods/lastIndexOf.ts
index 2f4088c..bc30b53 100644
--- a/inputs/passing/stringMethods/lastIndexOf.ts
+++ b/inputs/passing/stringMethods/lastIndexOf.ts
@@ -1,4 +1,4 @@
-// test_output! [[4,2,4,6],[-1,-1]]
+//! test_output([[4,2,4,6],[-1,-1]])
 
 export default function () {
   const positive = [
diff --git a/inputs/passing/stringMethods/padEnd.ts b/inputs/passing/stringMethods/padEnd.ts
index 7b23359..293ea49 100644
--- a/inputs/passing/stringMethods/padEnd.ts
+++ b/inputs/passing/stringMethods/padEnd.ts
@@ -1,4 +1,4 @@
-// test_output! ["foo  ","🚀","🚀","🚀","🚀","🚀","🚀🚀","🚀🚀","abc12","abc123","abc1231","abc12312"]
+//! test_output(["foo  ","🚀","🚀","🚀","🚀","🚀","🚀🚀","🚀🚀","abc12","abc123","abc1231","abc12312"])
 
 export default function () {
   return [
diff --git a/inputs/passing/stringMethods/padStart.ts b/inputs/passing/stringMethods/padStart.ts
index 1fc0986..f2bb54f 100644
--- a/inputs/passing/stringMethods/padStart.ts
+++ b/inputs/passing/stringMethods/padStart.ts
@@ -1,4 +1,4 @@
-// test_output! ["  foo","🚀","🚀","🚀","🚀","🚀","🚀🚀","🚀🚀","12abc","123abc","1231abc","12312abc"]
+//! test_output(["  foo","🚀","🚀","🚀","🚀","🚀","🚀🚀","🚀🚀","12abc","123abc","1231abc","12312abc"])
 
 export default function () {
   return [
diff --git a/inputs/passing/stringMethods/repeat.ts b/inputs/passing/stringMethods/repeat.ts
index 7e38c76..08e7670 100644
--- a/inputs/passing/stringMethods/repeat.ts
+++ b/inputs/passing/stringMethods/repeat.ts
@@ -1,4 +1,4 @@
-// test_output! "foofoofoo"
+//! test_output("foofoofoo")
 
 export default function () {
   return "foo".repeat(3);
diff --git a/inputs/passing/stringMethods/slice.ts b/inputs/passing/stringMethods/slice.ts
index 001bff1..8524c82 100644
--- a/inputs/passing/stringMethods/slice.ts
+++ b/inputs/passing/stringMethods/slice.ts
@@ -1,4 +1,4 @@
-// test_output! ["","","","🎨","🎨","🎨","한🎨","한🎨","🍹abc£한","🚀🍹abc£한🎨","🚀🍹abc£한🎨","🚀🍹abc£한🎨",""]
+//! test_output(["","","","🎨","🎨","🎨","한🎨","한🎨","🍹abc£한","🚀🍹abc£한🎨","🚀🍹abc£한🎨","🚀🍹abc£한🎨",""])
 
 export default function () {
   const str = "🚀🍹abc£한🎨";
diff --git a/inputs/passing/stringMethods/split.ts b/inputs/passing/stringMethods/split.ts
index 8a960a3..359c4d0 100644
--- a/inputs/passing/stringMethods/split.ts
+++ b/inputs/passing/stringMethods/split.ts
@@ -1,4 +1,4 @@
-// test_output! [["🚀","🍹","a","b","c","£","한","🎨"],["f","","bar"],["","bar"],["foo",""],["one","two","three"]]
+//! test_output([["🚀","🍹","a","b","c","£","한","🎨"],["f","","bar"],["","bar"],["foo",""],["one","two","three"]])
 
 export default function () {
   return [
diff --git a/inputs/passing/stringMethods/startsWith.ts b/inputs/passing/stringMethods/startsWith.ts
index 77c2f98..e2555b8 100644
--- a/inputs/passing/stringMethods/startsWith.ts
+++ b/inputs/passing/stringMethods/startsWith.ts
@@ -1,4 +1,4 @@
-// test_output! [[true,false,true,false,false,true]]
+//! test_output([[true,false,true,false,false,true]])
 
 export default function () {
   const startsWithTests = [
diff --git a/inputs/passing/stringMethods/substring.ts b/inputs/passing/stringMethods/substring.ts
index e122915..218949b 100644
--- a/inputs/passing/stringMethods/substring.ts
+++ b/inputs/passing/stringMethods/substring.ts
@@ -1,4 +1,4 @@
-// test_output! [["abc","de","abcde","cde","bcd"],["","abc",""],["abc","cde","bcd"]]
+//! test_output([["abc","de","abcde","cde","bcd"],["","abc",""],["abc","cde","bcd"]])
 
 export default function () {
   const positive = [
diff --git a/inputs/passing/stringMethods/toLowerCase.ts b/inputs/passing/stringMethods/toLowerCase.ts
index 2133d42..b80c7bc 100644
--- a/inputs/passing/stringMethods/toLowerCase.ts
+++ b/inputs/passing/stringMethods/toLowerCase.ts
@@ -1,4 +1,4 @@
-// test_output! [["abc","xyz","a1b2c3","hello world","áéíóú"]]
+//! test_output([["abc","xyz","a1b2c3","hello world","áéíóú"]])
 
 export default function () {
   const toLowerCaseTests = [
diff --git a/inputs/passing/stringMethods/toUpperCase.ts b/inputs/passing/stringMethods/toUpperCase.ts
index 5810ef8..822fdaf 100644
--- a/inputs/passing/stringMethods/toUpperCase.ts
+++ b/inputs/passing/stringMethods/toUpperCase.ts
@@ -1,4 +1,4 @@
-// test_output! [["ABC","XYZ","A1B2C3","HELLO WORLD","ÁÉÍÓÚ"]]
+//! test_output([["ABC","XYZ","A1B2C3","HELLO WORLD","ÁÉÍÓÚ"]])
 
 export default function () {
   const toUpperCaseTests = [
diff --git a/inputs/passing/stringMethods/trim.ts b/inputs/passing/stringMethods/trim.ts
index e9c9720..c8266ca 100644
--- a/inputs/passing/stringMethods/trim.ts
+++ b/inputs/passing/stringMethods/trim.ts
@@ -1,4 +1,4 @@
-// test_output! [["abc","abc","abc","a b c",""]]
+//! test_output([["abc","abc","abc","a b c",""]])
 
 export default function () {
   const trimTests = [
diff --git a/inputs/passing/stringMethods/trimEnd.ts b/inputs/passing/stringMethods/trimEnd.ts
index a35fa42..e30f167 100644
--- a/inputs/passing/stringMethods/trimEnd.ts
+++ b/inputs/passing/stringMethods/trimEnd.ts
@@ -1,4 +1,4 @@
-// test_output! [["abc","  abc","  abc","  a b c",""]]
+//! test_output([["abc","  abc","  abc","  a b c",""]])
 
 export default function () {
   const trimEndTests = [
diff --git a/inputs/passing/stringMethods/trimStart.ts b/inputs/passing/stringMethods/trimStart.ts
index 14ed558..eacf7c2 100644
--- a/inputs/passing/stringMethods/trimStart.ts
+++ b/inputs/passing/stringMethods/trimStart.ts
@@ -1,4 +1,4 @@
-// test_output! [["abc","abc  ","abc  ","a b c  ",""]]
+//! test_output([["abc","abc  ","abc  ","a b c  ",""]])
 
 export default function () {
   const trimStartTests = [
diff --git a/inputs/passing/swap.ts b/inputs/passing/swap.ts
index aa65582..be04830 100644
--- a/inputs/passing/swap.ts
+++ b/inputs/passing/swap.ts
@@ -1,4 +1,4 @@
-// test_output! ["b","a"]
+//! test_output(["b","a"])
 
 export default function main() {
   let x = ["a", "b"];
diff --git a/inputs/passing/testBinaryTree.ts b/inputs/passing/testBinaryTree.ts
index 7096ca1..fca5d40 100644
--- a/inputs/passing/testBinaryTree.ts
+++ b/inputs/passing/testBinaryTree.ts
@@ -1,4 +1,4 @@
-// test_output! [[1,2,5],[1,2,3,4,5]]
+//! test_output([[1,2,5],[1,2,3,4,5]])
 
 import BinaryTree from "./helpers/BinaryTree.ts";
 
diff --git a/inputs/passing/transitiveCapture.ts b/inputs/passing/transitiveCapture.ts
index d59296a..4d66305 100644
--- a/inputs/passing/transitiveCapture.ts
+++ b/inputs/passing/transitiveCapture.ts
@@ -1,4 +1,4 @@
-// test_output! 3
+//! test_output(3)
 
 export default function main() {
   const x = 3;
diff --git a/vstc/src/test_inputs.rs b/vstc/src/test_inputs.rs
index 4e30b54..e0e93b8 100644
--- a/vstc/src/test_inputs.rs
+++ b/vstc/src/test_inputs.rs
@@ -33,13 +33,19 @@ mod tests {
       let file_contents = fs::read_to_string(&file_path).expect("Failed to read file contents");
 
       if let Some(first_line) = file_contents.lines().next() {
-        if first_line.starts_with("// test_output! ") {
+        if first_line.starts_with("//! test_output(") {
           println!("\nTesting {} ...", file_path.to_str().unwrap());
 
-          let output_str = first_line
-            .split_once("// test_output! ")
+          let mut output_string = first_line
+            .split_once("//! test_output(")
             .map(|x| x.1)
-            .unwrap_or("");
+            .unwrap_or("")
+            .to_string();
+
+          if output_string.pop() != Some(')') {
+            println!("  Bad test_output format");
+            failed_paths.insert(file_path.clone());
+          }
 
           let resolved_path = resolve_entry_path(
             &file_path
@@ -86,15 +92,15 @@ mod tests {
 
           let result = vm.run(bytecode, Some(2_000_000), &[]);
 
-          let result_str = match result {
+          let result_string = match result {
             Ok(val) => val.codify(),
             Err(err) => format!("E: {}", err.codify()),
           };
 
-          if result_str != output_str {
+          if result_string != output_string {
             println!(
               "  Expected: \"{}\"\n  Actual:   \"{}\"\n",
-              output_str, result_str,
+              output_string, result_string,
             );
 
             failed_paths.insert(file_path.clone());