From 44ea79369c4387938c80b3a71182f463b565d3ce Mon Sep 17 00:00:00 2001
From: Zach Denton <z@chdenton.com>
Date: Mon, 26 Oct 2015 10:25:38 -0700
Subject: [PATCH 1/2] Improve error message when value is null.

Currently, when `value` is null, the error message is (for example) `Expected string, got object`. This changes the error message to `Expected string, got null`, which aids debugging.
---
 packages/check/match.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/check/match.js b/packages/check/match.js
index 1dd35bb3cf..9905f86339 100644
--- a/packages/check/match.js
+++ b/packages/check/match.js
@@ -152,7 +152,7 @@ var testSubtree = function (value, pattern) {
       if (typeof value === typeofChecks[i][1])
         return false;
       return {
-        message: "Expected " + typeofChecks[i][1] + ", got " + typeof value,
+        message: "Expected " + typeofChecks[i][1] + ", got " + (value === null ? "null" : typeof value),
         path: ""
       };
     }

From a7d90f6b59c84512f01dc7ec25f886a975b730fc Mon Sep 17 00:00:00 2001
From: Zach Denton <zach@scribd.com>
Date: Mon, 26 Oct 2015 11:42:27 -0700
Subject: [PATCH 2/2] Add tests for check error messages.

---
 packages/check/match_test.js | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/packages/check/match_test.js b/packages/check/match_test.js
index be74f40d28..0328ca1572 100644
--- a/packages/check/match_test.js
+++ b/packages/check/match_test.js
@@ -282,6 +282,37 @@ Tinytest.add("check - Match error path", function (test) {
   match({ "return": 0 }, { "return": String }, "[\"return\"]");
 });
 
+Tinytest.add("check - Match error message", function (test) {
+  var match = function (value, pattern, expectedMessage) {
+    try {
+      check(value, pattern);
+    } catch (err) {
+      if (err.message !== "Match error: " + expectedMessage)
+        test.fail({
+          type: "match-error-message",
+          message: "The message of Match.Error doesn't match.",
+          pattern: JSON.stringify(pattern),
+          value: JSON.stringify(value),
+          errorMessage: err.message,
+          expectedErrorMessage: expectedMessage
+        });
+    }
+  };
+
+  match(2, String, "Expected string, got number");
+  match({key: 0}, Number, "Expected number, got object");
+  match(null, Boolean, "Expected boolean, got null");
+  match("string", undefined, "Expected undefined, got string");
+  match(true, null, "Expected null, got true");
+  match("bar", "foo", "Expected foo, got \"bar\"");
+  match(3.14, Match.Integer, "Expected Integer, got 3.14");
+  match(false, [Boolean], "Expected array, got false");
+  match([null, null], [String], "Expected string, got null in field [0]");
+  match(2, {key: 2}, "Expected object, got number");
+  match(null, {key: 2}, "Expected object, got null");
+  match(new Date, {key: 2}, "Expected plain object");
+});
+
 // Regression test for https://github.com/meteor/meteor/issues/2136
 Meteor.isServer && Tinytest.addAsync("check - non-fiber check works", function (test, onComplete) {
   var Fiber = Npm.require('fibers');