BAEL-5209 example with JUnit5, Hamcrest and AssertJ

testing-modules/testing-assertions/src/main/java/com/baeldung/object/type/Deciduous.java

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+package com.baeldung.object.type;
+
+public class Deciduous implements Tree {
+
+    private String name;
+
+    public Deciduous(String name) {
+        this.name = name;
+    }
+
+    @Override
+    public boolean isEvergreen() {
+        return false;
+    }
+}

testing-modules/testing-assertions/src/main/java/com/baeldung/object/type/Evergreen.java

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+package com.baeldung.object.type;
+
+public class Evergreen implements Tree {
+
+    private String name;
+
+    public Evergreen(String name) {
+        this.name = name;
+    }
+
+
+    @Override
+    public boolean isEvergreen() {
+        return true;
+    }
+}

testing-modules/testing-assertions/src/main/java/com/baeldung/object/type/Tree.java

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+package com.baeldung.object.type;
+
+public interface Tree {
+
+    public boolean isEvergreen();
+}

testing-modules/testing-assertions/src/main/java/com/baeldung/object/type/TreeSorter.java

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+package com.baeldung.object.type;
+
+import java.util.List;
+
+public class TreeSorter {
+    protected Tree sortTree(String name) {
+
+        final List<String> deciduous = List.of("Beech", "Birch", "Ash", "Whitebeam", "Hornbeam", "Hazel & Willow");
+        final List<String> evergreen = List.of("Cedar", "Holly", "Laurel", "Olive", "Pine");
+
+        if (deciduous.contains(name)) {
+            return new Deciduous(name);
+        } else if (evergreen.contains(name)) {
+            return new Evergreen(name);
+        } else {
+            throw new RuntimeException("Tree could not be classified");
+        }
+    }
+}

testing-modules/testing-assertions/src/test/java/com/baeldung/object/type/TreeSorterAssertJUnitTest.java

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+package com.baeldung.object.type;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class TreeSorterAssertJUnitTest {
+    private final TreeSorter tested = new TreeSorter();
+
+    @Test
+    public void sortTreeShouldReturnEvergreen_WhenPineIsPassed() {
+        Tree tree = tested.sortTree("Pine");
+        assertThat(tree).isExactlyInstanceOf(Evergreen.class);
+    }
+
+    @Test
+    public void sortTreeShouldReturnDecidious_WhenBirchIsPassed() {
+        Tree tree = tested.sortTree("Birch");
+        assertThat(tree).hasSameClassAs(new Deciduous("Birch"));
+    }
+
+}

testing-modules/testing-assertions/src/test/java/com/baeldung/object/type/TreeSorterHamcrestUnitTest.java

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+package com.baeldung.object.type;
+
+import org.junit.jupiter.api.Test;
+
+import static org.hamcrest.CoreMatchers.instanceOf;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class TreeSorterHamcrestUnitTest {
+    private final TreeSorter tested = new TreeSorter();
+
+    @Test
+    public void sortTreeShouldReturnEvergreen_WhenPineIsPassed() {
+        Tree tree = tested.sortTree("Pine");
+        //with JUnit assertEquals:
+        assertEquals(tree.getClass(), Evergreen.class);
+        //with Hamcrest instanceOf:
+        assertThat(tree, instanceOf(Evergreen.class));
+
+    }
+
+    @Test
+    public void sortTreeShouldReturnDecidious_WhenBirchIsPassed() {
+        Tree tree = tested.sortTree("Birch");
+        assertThat(tree, instanceOf(Deciduous.class));
+    }
+
+}