BAEL-2444 Extra examples (eugenp#6087)

Author: earth001

core-java-8/src/test/java/com/baeldung/time/InstantUnitTest.java

@@ -0,0 +1,42 @@
+package com.baeldung.time;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.powermock.core.classloader.annotations.PrepareForTest;
+import org.powermock.modules.junit4.PowerMockRunner;
+
+import java.time.Clock;
+import java.time.Instant;
+import java.time.ZoneId;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.when;
+import static org.powermock.api.mockito.PowerMockito.mockStatic;
+
+@RunWith(PowerMockRunner.class)
+@PrepareForTest({ Instant.class })
+public class InstantUnitTest {
+
+    @Test
+    public void givenInstantMock_whenNow_thenGetFixedInstant() {
+        String instantExpected = "2014-12-22T10:15:30Z";
+        Clock clock = Clock.fixed(Instant.parse(instantExpected), ZoneId.of("UTC"));
+        Instant instant = Instant.now(clock);
+        mockStatic(Instant.class);
+        when(Instant.now()).thenReturn(instant);
+
+        Instant now = Instant.now();
+
+        assertThat(now.toString()).isEqualTo(instantExpected);
+    }
+
+    @Test
+    public void givenFixedClock_whenNow_thenGetFixedInstant() {
+        String instantExpected = "2014-12-22T10:15:30Z";
+        Clock clock = Clock.fixed(Instant.parse(instantExpected), ZoneId.of("UTC"));
+
+        Instant instant = Instant.now(clock);
+
+        assertThat(instant.toString()).isEqualTo(instantExpected);
+    }
+}

core-java-8/src/test/java/com/baeldung/time/InstantWithJMockUnitTest.java

@@ -0,0 +1,47 @@
+package com.baeldung.time;
+
+import mockit.Expectations;
+import mockit.Mock;
+import mockit.MockUp;
+import org.junit.jupiter.api.Test;
+
+import java.time.Clock;
+import java.time.Instant;
+import java.time.ZoneId;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class InstantWithJMockUnitTest {
+
+    @Test
+    public void givenInstantWithJMock_whenNow_thenGetFixedInstant() {
+        String instantExpected = "2014-12-21T10:15:30Z";
+        Clock clock = Clock.fixed(Instant.parse(instantExpected), ZoneId.of("UTC"));
+        new MockUp<Instant>() {
+            @Mock
+            public Instant now() {
+                return Instant.now(clock);
+            }
+        };
+
+        Instant now = Instant.now();
+
+        assertThat(now.toString()).isEqualTo(instantExpected);
+    }
+
+    @Test
+    public void givenInstantWithExpectations_whenNow_thenGetFixedInstant() {
+        Clock clock = Clock.fixed(Instant.parse("2014-12-23T10:15:30.00Z"), ZoneId.of("UTC"));
+        Instant instantExpected = Instant.now(clock);
+        new Expectations(Instant.class) {
+            {
+                Instant.now();
+                result = instantExpected;
+            }
+        };
+
+        Instant now = Instant.now();
+
+        assertThat(now).isEqualTo(instantExpected);
+    }
+}