diff --git a/libraries/src/test/java/com/baeldung/pairs/ApacheCommonsPairUnitTest.java b/libraries/src/test/java/com/baeldung/pairs/ApacheCommonsPairUnitTest.java
new file mode 100644
index 0000000000..0e6242b8a3
--- /dev/null
+++ b/libraries/src/test/java/com/baeldung/pairs/ApacheCommonsPairUnitTest.java
@@ -0,0 +1,50 @@
+package com.baeldung.pairs;
+
+import org.apache.commons.lang3.tuple.ImmutablePair;
+import org.apache.commons.lang3.tuple.MutablePair;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class ApacheCommonsPairUnitTest {
+
+    @Test
+    public void givenMutablePair_whenGetValue_shouldPass() {
+        int key = 5;
+        String value = "Five";
+
+        MutablePair<Integer, String> mutablePair = new MutablePair<>(key, value);
+        Assert.assertTrue(mutablePair.getKey() == key);
+        Assert.assertEquals(mutablePair.getValue(), value);
+    }
+
+    @Test
+    public void givenMutablePair_whenSetValue_shouldPass() {
+        int key = 6;
+        String value = "Six";
+        String newValue = "New Six";
+
+        MutablePair<Integer, String> mutablePair = new MutablePair<>(key, value);
+        Assert.assertTrue(mutablePair.getKey() == key);
+        Assert.assertEquals(mutablePair.getValue(), value);
+        mutablePair.setValue(newValue);
+        Assert.assertEquals(mutablePair.getValue(), newValue);
+    }
+
+    @Test
+    public void givenImmutablePair_whenGetValue_shouldPass() {
+        int key = 2;
+        String value = "Two";
+
+        ImmutablePair<Integer, String> immutablePair = new ImmutablePair<>(key, value);
+        Assert.assertTrue(immutablePair.getKey() == key);
+        Assert.assertEquals(immutablePair.getValue(), value);
+    }
+
+    @Test(expected = UnsupportedOperationException.class)
+    public void givenImmutablePair_whenSetValue_shouldFail() {
+        ImmutablePair<Integer, String> immutablePair = new ImmutablePair<>(1, "One");
+        immutablePair.setValue("Another One");
+    }
+
+
+}
diff --git a/libraries/src/test/java/com/baeldung/pairs/CoreJavaPairUnitTest.java b/libraries/src/test/java/com/baeldung/pairs/CoreJavaPairUnitTest.java
new file mode 100644
index 0000000000..ac258b9c77
--- /dev/null
+++ b/libraries/src/test/java/com/baeldung/pairs/CoreJavaPairUnitTest.java
@@ -0,0 +1,17 @@
+package com.baeldung.pairs;
+
+import javafx.util.Pair;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class CoreJavaPairUnitTest {
+    @Test
+    public void givenPair_whenGetValue_shouldSucceed() {
+        String key = "Good Day";
+        boolean value = true;
+        Pair<String, Boolean> pair = new Pair<>(key, value);
+
+        Assert.assertEquals(key, pair.getKey());
+        Assert.assertEquals(value, pair.getValue());
+    }
+}
\ No newline at end of file
diff --git a/libraries/src/test/java/com/baeldung/pairs/VavrPairsUnitTest.java b/libraries/src/test/java/com/baeldung/pairs/VavrPairsUnitTest.java
new file mode 100644
index 0000000000..9c318c7744
--- /dev/null
+++ b/libraries/src/test/java/com/baeldung/pairs/VavrPairsUnitTest.java
@@ -0,0 +1,29 @@
+package com.baeldung.pairs;
+
+import io.vavr.Tuple2;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class VavrPairsUnitTest {
+    @Test
+    public void givenTuple_whenSetValue_shouldSucceed() {
+        String key = "Eleven";
+        double value = 11.0;
+        double newValue = 11.1;
+
+        Tuple2<String, Double> pair = new Tuple2<>(key, value);
+
+        pair = pair.update2(newValue);
+        Assert.assertTrue(newValue == pair._2());
+    }
+
+    @Test
+    public void givenPair_whenGetValue_shouldSucceed() {
+        String key = "Twelve";
+        double value = 12.0;
+
+        Tuple2<String, Double> pair = new Tuple2<>(key, value);
+
+        Assert.assertTrue(value == pair._2());
+    }
+}
\ No newline at end of file