Merge pull request #494 from eugenp/grzegorz-master

Add AssertJ Java8 examples

assertj/src/test/java/com/baeldung/assertj/introduction/AssertJJava8Test.java

@@ -0,0 +1,132 @@
+package com.baeldung.assertj.introduction;
+
+import org.junit.Test;
+
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.LocalTime;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Optional;
+import java.util.function.Predicate;
+
+import static java.time.LocalDate.ofYearDay;
+import static java.util.Arrays.asList;
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class AssertJJava8Test {
+
+    @Test
+    public void givenOptional_shouldAssert() throws Exception {
+        final Optional<String> givenOptional = Optional.of("something");
+
+        assertThat(givenOptional)
+          .isPresent()
+          .hasValue("something");
+    }
+
+    @Test
+    public void givenPredicate_shouldAssert() throws Exception {
+        final Predicate<String> predicate = s -> s.length() > 4;
+
+        assertThat(predicate)
+          .accepts("aaaaa", "bbbbb")
+          .rejects("a", "b")
+          .acceptsAll(asList("aaaaa", "bbbbb"))
+          .rejectsAll(asList("a", "b"));
+    }
+
+    @Test
+    public void givenLocalDate_shouldAssert() throws Exception {
+        final LocalDate givenLocalDate = LocalDate.of(2016, 7, 8);
+        final LocalDate todayDate = LocalDate.now();
+
+        assertThat(givenLocalDate)
+          .isBefore(LocalDate.of(2020, 7, 8))
+          .isAfterOrEqualTo(LocalDate.of(1989, 7, 8));
+
+        assertThat(todayDate)
+          .isAfter(LocalDate.of(1989, 7, 8))
+          .isToday();
+    }
+
+    @Test
+    public void givenLocalDateTime_shouldAssert() throws Exception {
+        final LocalDateTime givenLocalDate = LocalDateTime.of(2016, 7, 8, 12, 0);
+
+        assertThat(givenLocalDate)
+          .isBefore(LocalDateTime.of(2020, 7, 8, 11, 2));
+    }
+
+    @Test
+    public void givenLocalTime_shouldAssert() throws Exception {
+        final LocalTime givenLocalTime = LocalTime.of(12, 15);
+
+        assertThat(givenLocalTime)
+          .isAfter(LocalTime.of(1, 0))
+          .hasSameHourAs(LocalTime.of(12, 0));
+    }
+
+    @Test
+    public void givenList_shouldAssertFlatExtracting() throws Exception {
+        final List<LocalDate> givenList = asList(ofYearDay(2016, 5), ofYearDay(2015, 6));
+
+        assertThat(givenList)
+          .flatExtracting(LocalDate::getYear)
+          .contains(2015);
+    }
+
+    @Test
+    public void givenList_shouldAssertFlatExtractingLeapYear() throws Exception {
+        final List<LocalDate> givenList = asList(ofYearDay(2016, 5), ofYearDay(2015, 6));
+
+        assertThat(givenList)
+          .flatExtracting(LocalDate::isLeapYear)
+          .contains(true);
+    }
+
+    @Test
+    public void givenList_shouldAssertFlatExtractingClass() throws Exception {
+        final List<LocalDate> givenList = asList(ofYearDay(2016, 5), ofYearDay(2015, 6));
+
+        assertThat(givenList)
+          .flatExtracting(Object::getClass)
+          .contains(LocalDate.class);
+    }
+
+    @Test
+    public void givenList_shouldAssertMultipleFlatExtracting() throws Exception {
+        final List<LocalDate> givenList = asList(ofYearDay(2016, 5), ofYearDay(2015, 6));
+
+        assertThat(givenList)
+          .flatExtracting(LocalDate::getYear, LocalDate::getDayOfMonth)
+          .contains(2015, 6);
+    }
+
+    @Test
+    public void givenString_shouldSatisfy() throws Exception {
+        final String givenString = "someString";
+
+        assertThat(givenString)
+          .satisfies(s -> {
+              assertThat(s).isNotEmpty();
+              assertThat(s).hasSize(10);
+          });
+    }
+
+    @Test
+    public void givenString_shouldMatch() throws Exception {
+        final String emptyString = "";
+
+        assertThat(emptyString)
+          .matches(String::isEmpty);
+    }
+
+    @Test
+    public void givenList_shouldHasOnlyOneElementSatisfying() throws Exception {
+        final List<String> givenList = Arrays.asList("");
+
+        assertThat(givenList)
+          .hasOnlyOneElementSatisfying(s -> assertThat(s).isEmpty());
+    }
+}