feat(typescript): do not mutate interfaces (#1662)

stryker-mutator · Sep 18, 2019 · 86b2ffe · 86b2ffe
1 parent 97f0f7e
commit 86b2ffe
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Showing 2 changed files with 29 additions and 3 deletions.
diff --git a/packages/typescript/src/TypescriptMutator.ts b/packages/typescript/src/TypescriptMutator.ts
@@ -18,7 +18,7 @@ export const MUTATORS_TOKEN = 'mutators';
 export class TypescriptMutator {
 
   public static inject = tokens(commonTokens.options, MUTATORS_TOKEN);
-  constructor(private readonly options: StrykerOptions, public mutators: ReadonlyArray<NodeMutator>) { }
+  constructor(private readonly options: StrykerOptions, public readonly mutators: ReadonlyArray<NodeMutator>) { }
 
   public mutate(inputFiles: File[]): Mutant[] {
     const tsConfig = getTSConfig(this.options);
@@ -37,13 +37,14 @@ export class TypescriptMutator {
       const mutants = flatMap(targetMutators, mutator => mutator.mutate(node, sourceFile));
       node.forEachChild(child => {
         // It is important that forEachChild does not return a true, otherwise node visiting is halted!
-        mutants.push(... this.mutateForNode(child, sourceFile));
+        mutants.push(...this.mutateForNode(child, sourceFile));
       });
       return mutants;
     }
   }
 }
 
 const shouldNodeBeSkipped = (node: ts.Node): boolean => {
-  return node.modifiers !== undefined && node.modifiers.some(modifier => modifier.kind === ts.SyntaxKind.DeclareKeyword);
+  return node.kind === ts.SyntaxKind.InterfaceDeclaration ||
+    node.modifiers !== undefined && node.modifiers.some(modifier => modifier.kind === ts.SyntaxKind.DeclareKeyword);
 };
diff --git a/packages/typescript/test/unit/TypescriptMutator.spec.ts b/packages/typescript/test/unit/TypescriptMutator.spec.ts
@@ -150,6 +150,31 @@ describe('TypescriptMutator', () => {
           }
         ]);
       });
+
+      it('should skip a node when it is an interface', () => {
+        // Arrange
+        file1 = new File(
+          'file1.ts',
+          `interface Hello {
+            value: string;
+            sortable?: true;
+          }`);
+
+        // Act
+        const mutants = sut.mutate([
+          file1,
+        ]);
+
+        // Assert
+        expect(mutants).to.deep.equal([
+          {
+            fileName: 'file1.ts',
+            mutatorName: 'SourceFileForTest',
+            range: [0, 85],
+            replacement: '"stryker was here"',
+          }
+        ]);
+      });
     });
 
   });