[#6] cover the models module with junit tests

Signed-off-by: Ori Bruk <o.bruk@yadro.com>

models/src/test/java/info/frostfs/sdk/UuidExtensionTest.java

@@ -0,0 +1,57 @@
+package info.frostfs.sdk;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.UUID;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+public class UuidExtensionTest {
+    private static final UUID TEST_UUID = UUID.fromString("ca70c669-0294-432d-8b83-05fc1475a579");
+    private static final byte[] TEST_UUID_BYTES =
+            new byte[]{-54, 112, -58, 105, 2, -108, 67, 45, -117, -125, 5, -4, 20, 117, -91, 121};
+
+    @Test
+    void uuidAsBytes_success() {
+        //When
+        var result = UuidExtension.asBytes(TEST_UUID);
+
+        //Then
+        assertThat(result).hasSize(16).containsExactly(TEST_UUID_BYTES);
+    }
+
+    @Test
+    void uuidAsBytes_givenParamsIsNull() {
+        //When + Then
+        assertThrows(IllegalArgumentException.class, () -> UuidExtension.asBytes(null));
+    }
+
+    @Test
+    void bytesAsUuid_success() {
+        //When
+        var result = UuidExtension.asUuid(TEST_UUID_BYTES);
+
+        //Then
+        assertEquals(TEST_UUID, result);
+    }
+
+    @Test
+    void bytesAsUuid_givenParamsIsNull() {
+        //When + Then
+        assertThrows(IllegalArgumentException.class, () -> UuidExtension.asUuid(null));
+    }
+
+    @Test
+    void bytesAsUuid_wrongArraySize() {
+        //Given
+        var valueLength15 = new byte[]{-54, 112, -58, 105, 2, -108, 67, 45, -117, -125, 5, -4, 20, 117, -91};
+        var valueLength17 = new byte[]{-54, 112, -58, 105, 2, -108, 67, 45, -117, -125, 5, -4, 20, 117, -91, 121, 12};
+
+
+        //When + Then
+        assertThrows(IllegalArgumentException.class, () -> UuidExtension.asUuid(valueLength15));
+        assertThrows(IllegalArgumentException.class, () -> UuidExtension.asUuid(valueLength17));
+    }
+}