feat(string mutations): don't mutate Symbol descriptions (#4407)

Don't mutate `Symbol('foo')` (but still mutate `Symbol('foo' + bar)`).
stryker-mutator · Sep 22, 2023 · bdd0d5c · bdd0d5c
1 parent f589ca8
commit bdd0d5c
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Showing 2 changed files with 16 additions and 1 deletion.
diff --git a/packages/instrumenter/src/mutators/string-literal-mutator.ts b/packages/instrumenter/src/mutators/string-literal-mutator.ts
@@ -31,6 +31,7 @@ function isValidParent(child: NodePath<babel.types.StringLiteral>): boolean {
     types.isObjectMethod(parent) ||
     (types.isObjectProperty(parent) && parent.key === child.node) ||
     (types.isClassProperty(parent) && parent.key === child.node) ||
-    (types.isCallExpression(parent) && types.isIdentifier(parent.callee, { name: 'require' }))
+    (types.isCallExpression(parent) && types.isIdentifier(parent.callee, { name: 'require' })) ||
+    (types.isCallExpression(parent) && types.isIdentifier(parent.callee, { name: 'Symbol' }))
   );
 }
diff --git a/packages/instrumenter/test/unit/mutators/string-literal-mutator.spec.ts b/packages/instrumenter/test/unit/mutators/string-literal-mutator.spec.ts
@@ -39,6 +39,20 @@ describe(sut.name, () => {
       expectJSMutation(sut, '"use strict";"use asm";');
       expectJSMutation(sut, 'function a() {"use strict";"use asm";}');
     });
+
+    it('should not mutate string literals in symbols with descriptions', () => {
+      expectJSMutation(sut, "const a = Symbol('foo');");
+      expectJSMutation(sut, 'const a = Symbol("foo");');
+    });
+
+    it('should not mutate symbols without description', () => {
+      expectJSMutation(sut, 'const a = Symbol();');
+    });
+
+    it('should mutate template literals in symbols with descriptions', () => {
+      expectJSMutation(sut, 'const a = Symbol(`foo`);', 'const a = Symbol(``);');
+      expectJSMutation(sut, "const a = Symbol('foo' + 'bar');", 'const a = Symbol(\'foo\' + "");', 'const a = Symbol("" + \'bar\');');
+    });
   });
 
   describe('imports/exports', () => {