Feat: DatabaseConnectionTest implemented

helpmehelpapplication/src/test/java/ntnu/systemutvikling/team6/database/DatabaseConnectionTest.java

@@ -0,0 +1,56 @@
+package ntnu.systemutvikling.team6.database;
+
+import org.junit.jupiter.api.Test;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class DatabaseConnectionTest {
+
+    @Test
+    void constructorShouldCreateInstanceWithValidCredentials() {
+        DatabaseConnection db = new DatabaseConnection(
+                "jdbc:mysql://localhost:3306/test",
+                "user",
+                "password"
+        );
+
+        assertNotNull(db);
+    }
+
+    @Test
+    void constructorShouldThrowExceptionIfUrlIsNull() {
+        assertThrows(IllegalArgumentException.class, () -> {
+            new DatabaseConnection(null, "user", "password");
+        });
+    }
+
+    @Test
+    void constructorShouldThrowExceptionIfUsernameIsBlank() {
+        assertThrows(IllegalArgumentException.class, () -> {
+            new DatabaseConnection("jdbc:mysql://localhost:3306/test", "", "password");
+        });
+    }
+
+    @Test
+    void constructorShouldThrowExceptionIfPasswordIsBlank() {
+        assertThrows(IllegalArgumentException.class, () -> {
+            new DatabaseConnection("jdbc:mysql://localhost:3306/test", "user", "");
+        });
+    }
+
+    @Test
+    void getMySqlConnectionShouldReturnConnection() throws SQLException {
+
+        DatabaseConnection db = new DatabaseConnection();
+
+        Connection connection = db.getMySqlConnection();
+
+        assertNotNull(connection);
+        assertFalse(connection.isClosed());
+
+        connection.close();
+    }
+}