Tests: Add module-nested.js test case

This asserts the undesirable status quo, where the stack is left
in a bad state if the module closure encounters a global error while
test suites are still being loaded.

Ref qunitjs#1478.

test/cli/fixtures/expected/tap-outputs.js

@@ -323,6 +323,16 @@ ok 3 module B > test D
 # pass 2
 # skip 1
 # todo 1
+# fail 0`,
+
+	"qunit module-nested.js":
+`TAP version 13
+ok 1 module 1 > test in module 1
+ok 2 module 2 > module 3 > test in module 3
+1..2
+# pass 2
+# skip 0
+# todo 0
 # fail 0`,
 
 	"qunit incorrect-hooks-warning/test.js":

test/cli/fixtures/module-nested.js

@@ -0,0 +1,37 @@
+try {
+	QUnit.module( "module 1", () => {
+		QUnit.test( "test in module 1", assert => {
+			assert.true( true );
+		} );
+	} );
+} catch ( e ) {
+
+	// Ignore
+}
+
+try {
+	QUnit.module( "module 2", () => {
+
+		// trigger an error in executeNow
+		undefined();
+
+		QUnit.test( "test in module  2", assert => {
+			assert.true( true );
+		} );
+	} );
+} catch ( e ) {
+
+	// Ignore
+}
+
+
+try {
+	QUnit.module( "module 3", () => {
+		QUnit.test( "test in module 3", assert => {
+			assert.true( true );
+		} );
+	} );
+} catch ( e ) {
+
+	// Ignore
+}

test/cli/main.js

@@ -657,6 +657,15 @@ CALLBACK: done`;
 		} );
 	} );
 
+	// Regression test for https://github.com/qunitjs/qunit/issues/1478
+	QUnit.test( "nested module scopes", async assert => {
+		const command = "qunit module-nested.js";
+		const execution = await execute( command );
+
+		assert.equal( execution.code, 0 );
+		assert.equal( execution.stdout, expectedOutput[ command ] );
+	} );
+
 	QUnit.test( "warns about incorrect hook usage", async assert => {
 		const command = "qunit incorrect-hooks-warning/test.js";
 		const execution = await execute( command );