Implement mutationLevel construct BlockStatement

packages/instrumenter/src/mutators/block-statement-mutator.ts

@@ -7,8 +7,8 @@ const { types } = babel;
 export const blockStatementMutator: NodeMutator = {
   name: 'BlockStatement',
 
-  *mutate(path) {
-    if (path.isBlockStatement() && isValid(path)) {
+  *mutate(path, options) {
+    if (path.isBlockStatement() && isValid(path) && isInMutationLevel(options)) {
       yield types.blockStatement([]);
     }
   },
@@ -69,3 +69,7 @@ function hasSuperExpressionOnFirstLine(constructor: NodePath<babel.types.BlockSt
     types.isSuper(constructor.node.body[0].expression.callee)
   );
 }
+
+function isInMutationLevel(operations: string[] | undefined): boolean {
+  return operations === undefined || operations.length > 0;
+}

packages/instrumenter/test/unit/mutators/block-statement-mutator.spec.ts

@@ -1,7 +1,11 @@
 import { expect } from 'chai';
 
 import { blockStatementMutator as sut } from '../../../src/mutators/block-statement-mutator.js';
-import { expectJSMutation } from '../../helpers/expect-mutation.js';
+import { expectJSMutation, expectJSMutationWithLevel } from '../../helpers/expect-mutation.js';
+import { MutationLevel } from '../../../src/mutation-level/mutation-level.js';
+
+const blockStatementLevel: MutationLevel = { name: 'BlockStatementLevel', BlockStatement: ['BlockStatement'] };
+const blockStatementUndefinedLevel: MutationLevel = { name: 'BlockStatementLevel' };
 
 describe(sut.name, () => {
   it('should have name "BlockStatement"', () => {
@@ -70,5 +74,22 @@ describe(sut.name, () => {
     it('should not mutate a constructor containing a super call and contains initialized properties', () => {
       expectJSMutation(sut, 'class Foo extends Bar { private baz = "qux"; constructor() { super(); } }');
     });
+
+    it('should only mutate what is defined in the mutator level', () => {
+      expectJSMutationWithLevel(sut, blockStatementLevel.BlockStatement, 'class Foo { constructor() { bar(); } }', 'class Foo { constructor() {} }');
+    });
+
+    it('should not mutate anything if there are no values in the mutation level', () => {
+      expectJSMutationWithLevel(sut, [], 'class Foo { constructor() { bar(); } }');
+    });
+
+    it('should mutate everything if the mutation level is undefined', () => {
+      expectJSMutationWithLevel(
+        sut,
+        blockStatementUndefinedLevel.BlockStatement,
+        'class Foo { constructor() { bar(); } }',
+        'class Foo { constructor() {} }',
+      );
+    });
   });
 });