[str-to-uuid] uuid from string (#13736)

* [str-to-uuid] uuid from string

* [str-to-uuid] rename test methods

core-java-modules/core-java-uuid/src/test/java/com/baeldung/uuid/UUIDFromStringUnitTest.java

@@ -0,0 +1,62 @@
+package com.baeldung.uuid;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.UUID;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class UUIDFromStringUnitTest {
+    @Test
+    void whenStringInUUIDFormat_thenFromStringWorks() {
+        String inputStr = "bbcc4621-d88f-4a94-ae2f-b38072bf5087";
+        
+        UUID uuid = UUID.fromString(inputStr);
+        UUID uuid2 = UUID.fromString(inputStr);
+        UUID uuid3 = UUID.fromString(inputStr);
+
+        assertEquals(inputStr, uuid.toString());
+
+        assertEquals(uuid, uuid2);
+        assertEquals(uuid, uuid3);
+
+    }
+
+    @Test
+    void whenStringNotInUUIDFormat_thenFromStringRaisesException() {
+        String inputStr = "I am not a standard UUID representation.";
+        assertThrows(IllegalArgumentException.class, () -> UUID.fromString(inputStr));
+    }
+
+    @Test
+    void whenStringInFreeFormat_thenNameUUIDFromBytesWorks() {
+        String inputStr = "I am not a standard UUID representation.";
+
+        UUID uuid = UUID.nameUUIDFromBytes(inputStr.getBytes());
+        UUID uuid2 = UUID.nameUUIDFromBytes(inputStr.getBytes());
+        UUID uuid3 = UUID.nameUUIDFromBytes(inputStr.getBytes());
+
+        assertTrue(uuid != null);
+
+        assertEquals(uuid, uuid2);
+        assertEquals(uuid, uuid3);
+
+        assertEquals(3, uuid.version());
+    }
+
+    @Test
+    void whenStringInFreeFormat_thenGenerateVer5UUIDWorks() {
+        String inputStr = "I am not a standard UUID representation.";
+
+        UUID uuid = UUIDGenerator.generateType5UUID(inputStr);
+        UUID uuid2 = UUIDGenerator.generateType5UUID(inputStr);
+        UUID uuid3 = UUIDGenerator.generateType5UUID(inputStr);
+
+        assertEquals(5, uuid.version());
+
+        assertTrue(uuid != null);
+
+        assertEquals(uuid, uuid2);
+        assertEquals(uuid, uuid3);
+    }
+}