Add junit-mockito module: 30 runnable JUnit 6.1.3 / Mockito 5.24.0 interview answers

One test per question, each writing and asserting its own transcript under output/. Covers lifecycle, extensions, parameterized and dynamic tests, mocks vs spies, verification, strict stubs, static and constructor mocking, and flaky tests. Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01CifR2BE7PBvRy5hT8TS9oz
2026-10-26 01:52:44 +00:00
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+package lab.jm;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.mock;
+
+import java.time.Clock;
+import java.time.Instant;
+import java.time.ZoneOffset;
+import java.util.Map;
+import lab.jm.fixtures.FlakyFixtures;
+import org.junit.jupiter.api.MethodOrderer;
+import org.junit.jupiter.api.Test;
+
+/** Q29 and Q30: flaky tests. */
+class F_FlakyTest extends Lab {
+
+    @Test
+    void q29_orderDependenceAndTime() {
+        q(29, "flaky-order-and-time");
+        FlakyFixtures.SharedState.REGISTRY.clear();
+        Run forward = Run.of(FlakyFixtures.SharedState.class,
+                Map.of("junit.jupiter.testmethod.order.default", MethodOrderer.MethodName.class.getName()));
+        FlakyFixtures.SharedState.REGISTRY.clear();
+        Run reverse = Run.of(FlakyFixtures.SharedState.class,
+                Map.of("junit.jupiter.testmethod.order.default", FlakyFixtures.ReverseOrder.class.getName()));
+        p("--- order a_, b_ (alphabetical) ---");
+        forward.events.forEach(e -> p("%s", e));
+        p("--- order b_, a_ (reversed) ---");
+        reverse.events.forEach(e -> p("%s", e));
+        reverse.failures.forEach(f -> p("  %s: %s", f.getClass().getSimpleName(), f.getMessage()));
+
+        PaymentGateway gw = mock(PaymentGateway.class);
+        Clock morning = Clock.fixed(Instant.parse("2026-10-26T10:00:00Z"), ZoneOffset.UTC);
+        Clock night = Clock.fixed(Instant.parse("2026-10-26T23:30:00Z"), ZoneOffset.UTC);
+        p("--- time: the same code with an injected Clock ---");
+        p("acceptsOrders() at 10:00 UTC : %s", new OrderService(gw, morning).acceptsOrders());
+        p("acceptsOrders() at 23:30 UTC : %s", new OrderService(gw, night).acceptsOrders());
+        assertTrue(forward.failures.isEmpty());
+        assertEquals(1, reverse.failures.size());
+        assertTrue(new OrderService(gw, morning).acceptsOrders());
+        assertFalse(new OrderService(gw, night).acceptsOrders());
+    }
+
+    @Test
+    void q30_repeatedTestFailureThreshold() {
+        q(30, "repeated-test-failure-threshold");
+        Run run = Run.of(FlakyFixtures.Intermittent.class);
+        run.events.forEach(e -> p("%s", e));
+        long failed = run.events.stream().filter(e -> e.endsWith("FAILED")).count();
+        long skipped = run.events.stream().filter(e -> e.contains("SKIPPED")).count();
+        p("failed=%d skipped=%d", failed, skipped);
+        assertTrue(failed >= 2);
+    }
+}