Add spec for invalid settings notification

spec/fixtures/packages/package-with-invalid-settings/package.json

@@ -0,0 +1,4 @@
+{
+  "name": "package-with-invalid-settings",
+  "version": "1.0.0"
+}

spec/fixtures/packages/package-with-invalid-settings/settings/settings.json

@@ -0,0 +1 @@
+><

spec/package-manager-spec.coffee

@@ -239,6 +239,19 @@ describe "PackageManager", ->
             expect(addErrorHandler.callCount).toBe 1
             expect(addErrorHandler.argsForCall[0][0].message).toContain("Failed to load a package-with-invalid-grammar package grammar")
 
+        it "adds a notification when the settings are invalid", ->
+          addErrorHandler = jasmine.createSpy()
+          atom.notifications.onDidAddNotification(addErrorHandler)
+
+          expect(-> atom.packages.activatePackage('package-with-invalid-settings')).not.toThrow()
+
+          waitsFor ->
+            addErrorHandler.callCount > 0
+
+          runs ->
+            expect(addErrorHandler.callCount).toBe 1
+            expect(addErrorHandler.argsForCall[0][0].message).toContain("Failed to load the package-with-invalid-settings package settings")
+
     describe "when the package has no main module", ->
       it "does not throw an exception", ->
         spyOn(console, "error")

src/package.coffee

@@ -324,7 +324,7 @@ class Package
       ScopedProperties.load settingsPath, (error, settings) =>
         if error?
           detail = "#{error.message} in #{settingsPath}"
-          stack += "#{error.stack}\n  at #{settingsPath}:1:1"
+          stack = "#{error.stack}\n  at #{settingsPath}:1:1"
           atom.notifications.addFatalError("Failed to load the #{@name} package settings", {stack, detail, dismissable: true})
         else
           @settings.push(settings)