implement tests

ui/src/app/pipes/eta.pipe.spec.ts

@@ -0,0 +1,26 @@
+import { EtaPipe } from './eta.pipe';
+
+describe('EtaPipe', () => {
+  it('returns null for null input', () => {
+    const pipe = new EtaPipe();
+    expect(pipe.transform(null as unknown as number)).toBeNull();
+  });
+
+  it('formats seconds under one minute', () => {
+    const pipe = new EtaPipe();
+    expect(pipe.transform(0)).toBe('0s');
+    expect(pipe.transform(59)).toBe('59s');
+  });
+
+  it('formats minutes and seconds', () => {
+    const pipe = new EtaPipe();
+    expect(pipe.transform(60)).toBe('1m 0s');
+    expect(pipe.transform(90)).toBe('1m 30s');
+  });
+
+  it('formats hours', () => {
+    const pipe = new EtaPipe();
+    expect(pipe.transform(3600)).toBe('1h 0m 0s');
+    expect(pipe.transform(3661)).toBe('1h 1m 1s');
+  });
+});