eugenp · maibin · Nov 17, 2025 · Nov 11, 2025
diff --git a/...main/java/com/baeldung/resolvingjunitconstructorerror/ResolvingJUnitConstructorError.java b/...main/java/com/baeldung/resolvingjunitconstructorerror/ResolvingJUnitConstructorError.java
@@ -0,0 +1,8 @@
+package com.baeldung.resolvingjunitconstructorerror;
+
+public class ResolvingJUnitConstructorError {
+
+    public int square(int a) {
+        return a * a;
+    }
+}
diff --git a/...baeldung/resolvingjunitconstructorerror/ResolvingJUnitConstructorErrorJUnit4UnitTest.java b/...baeldung/resolvingjunitconstructorerror/ResolvingJUnitConstructorErrorJUnit4UnitTest.java
@@ -0,0 +1,29 @@
+package com.baeldung.resolvingjunitconstructorerror;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import java.util.Arrays;
+import java.util.Collection;
+import static org.junit.Assert.assertEquals;
+
+@RunWith(Parameterized.class)
+public class ResolvingJUnitConstructorErrorJUnit4UnitTest {
+
+    private final int input;
+    private final ResolvingJUnitConstructorError service = new ResolvingJUnitConstructorError();
+
+    public ResolvingJUnitConstructorErrorJUnit4UnitTest(int input) {
+        this.input = input;
+    }
+
+    @Parameterized.Parameters
+    public static Collection<Object[]> data() {
+        return Arrays.asList(new Object[][]{{2}, {3}, {4}});
+    }
+
+    @Test
+    public void givenNumber_whenSquare_thenReturnsCorrectResult() {
+        assertEquals(input * input, service.square(input));
+    }
+}
diff --git a/...baeldung/resolvingjunitconstructorerror/ResolvingJUnitConstructorErrorJUnit5UnitTest.java b/...baeldung/resolvingjunitconstructorerror/ResolvingJUnitConstructorErrorJUnit5UnitTest.java
@@ -0,0 +1,16 @@
+package com.baeldung.resolvingjunitconstructorerror;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class ResolvingJUnitConstructorErrorJUnit5UnitTest {
+
+    private final ResolvingJUnitConstructorError service = new ResolvingJUnitConstructorError();
+
+    @ParameterizedTest
+    @ValueSource(ints = {2, 3, 4})
+    void givenNumber_whenSquare_thenReturnsCorrectResult(int input) {
+        assertEquals(input * input, service.square(input));
+    }
+}
diff --git a/...lvingjunitconstructorerror/ResolvingJUnitConstructorErrorNoConstructorJUnit4UnitTest.java b/...lvingjunitconstructorerror/ResolvingJUnitConstructorErrorNoConstructorJUnit4UnitTest.java
@@ -0,0 +1,22 @@
+package com.baeldung.resolvingjunitconstructorerror;
+
+import org.junit.Before;
+import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+
+public class ResolvingJUnitConstructorErrorNoConstructorJUnit4UnitTest {
+
+    private ResolvingJUnitConstructorError service;
+    private int input;
+
+    @Before
+    public void setUp() {
+        service = new ResolvingJUnitConstructorError();
+        input = 2;
+    }
+
+    @Test
+    public void givenNumber_whenSquare_thenReturnsCorrectResult() {
+        assertEquals(input * input, service.square(input));
+    }
+}
diff --git a/...lvingjunitconstructorerror/ResolvingJUnitConstructorErrorNoConstructorJUnit5UnitTest.java b/...lvingjunitconstructorerror/ResolvingJUnitConstructorErrorNoConstructorJUnit5UnitTest.java
@@ -0,0 +1,22 @@
+package com.baeldung.resolvingjunitconstructorerror;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class ResolvingJUnitConstructorErrorNoConstructorJUnit5UnitTest {
+
+    private ResolvingJUnitConstructorError service;
+    private int input;
+
+    @BeforeEach
+    void setUp() {
+        service = new ResolvingJUnitConstructorError();
+        input = 2;
+    }
+
+    @Test
+    void givenNumber_whenSquare_thenReturnsCorrectResult() {
+        assertEquals(input * input, service.square(input));
+    }
+}
diff --git a/...ldung/resolvingjunitconstructorerror/ResolvingJUnitConstructorErrorReproduceUnitTest.java b/...ldung/resolvingjunitconstructorerror/ResolvingJUnitConstructorErrorReproduceUnitTest.java
@@ -0,0 +1,21 @@
+package com.baeldung.resolvingjunitconstructorerror;
+
+import org.junit.Ignore;
+import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+
+@Ignore("Demonstrates JUnit constructor error")
+public class ResolvingJUnitConstructorErrorReproduceUnitTest {
+
+    private int input;
+
+    public ResolvingJUnitConstructorErrorReproduceUnitTest(int input) {
+        this.input = input;
+    }
+
+    @Test
+    public void givenNumber_whenSquare_thenReturnsCorrectResult() {
+        ResolvingJUnitConstructorError service = new ResolvingJUnitConstructorError();
+        assertEquals(input * input, service.square(input));
+    }
+}