feat(ng-dev): add staticTest()

projects/integration/src/app/api-tests/ng-dev.spec.ts

@@ -9,6 +9,7 @@ import {
   logTimers,
   marbleTest,
   SlTestRequest,
+  staticTest,
   TestCall,
 } from '@s-libs/ng-dev';
 
@@ -56,4 +57,8 @@ describe('ng-dev', () => {
   it('has marbleTest', () => {
     expect(marbleTest).toBeDefined();
   });
+
+  it('has staticTest', () => {
+    expect(staticTest).toBeDefined();
+  });
 });

projects/ng-dev/src/lib/static-test.spec.ts

@@ -0,0 +1,35 @@
+import { noop } from '@s-libs/micro-dash';
+import { staticTest } from './static-test';
+
+let curSpec!: jasmine.SpecResult;
+jasmine.getEnv().addReporter({
+  specStarted(result) {
+    curSpec = result;
+  },
+});
+
+describe('testTyping()', () => {
+  it('satisfies jasmine that the test expects something', () => {
+    staticTest(noop);
+    expect(curSpec.passedExpectations.length).toBe(1);
+  });
+
+  it('does not execute the code', () => {
+    staticTest(() => {
+      fail('this should not run');
+    });
+  });
+
+  describe('example from the docs', () => {
+    function reject<T>(array: T[], predicate: (value: T) => boolean): T[] {
+      return array.filter((value) => !predicate(value));
+    }
+
+    it('requires the predicate type to match the array type', () => {
+      staticTest(() => {
+        // @ts-expect-error -- mismatch of number array w/ string function
+        reject([1, 2, 3], (value: string) => value === '2');
+      });
+    });
+  });
+});

projects/ng-dev/src/lib/static-test.ts

@@ -0,0 +1,18 @@
+/**
+ * Use this when you want to write test code that doesn't actually run, instead relying only on your static tools like Typescript or a linter to raise errors.
+ *
+ * ```ts
+ * function reject<T>(array: T[], predicate: (value: T) => boolean): T[] {
+ *   return array.filter((value) => !predicate(value));
+ * }
+ *
+ * it('requires the predicate type to match the array type', () => {
+ *   staticTest(() => {
+ *     // @ts-expect-error -- mismatch of number array w/ string function
+ *     reject([1, 2, 3], (value: string) => value === '2');
+ *   });
+ * }); * ```
+ */
+export function staticTest(_test: VoidFunction): void {
+  expect().nothing();
+}

projects/ng-dev/src/public-api.ts

@@ -8,3 +8,4 @@ export * from './lib/component-context/index';
 export * from './lib/test-requests/index';
 export { logTimers } from './lib/log-timers';
 export { marbleTest } from './lib/marble-test';
+export { staticTest } from './lib/static-test';