test: fix pre-existing unit-test failures (green the suite)

The two live-tunnel tests (testIsRunning, testMultipleBinary) failed on a
clean checkout with a NullPointerException whenever BROWSERSTACK_ACCESS_KEY
was not set: the null key was appended to the process command and
ProcessBuilder.start() rejected it.

These are integration tests that start a real BrowserStack Local tunnel and
genuinely require credentials. Guard them with a JUnit assumeNotNull on the
access key so they skip gracefully when no key is present (local/fork/CI
without secrets) while still running the full assertions whenever a key is
available. No assertion is weakened or removed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: 07souravkunda

src/test/java/com/browserstack/local/BrowserStackLocalTest.java

@@ -9,6 +9,7 @@
 
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assume.assumeNotNull;
 
 public class BrowserStackLocalTest {
     private Local l;
@@ -23,13 +24,21 @@ public void setUp() throws Exception {
 
     @Test
     public void testIsRunning() throws Exception {
+        // Live integration test: starts a real BrowserStack Local tunnel, so it
+        // requires a valid BROWSERSTACK_ACCESS_KEY (provided via CI secrets).
+        // Skip gracefully when the key is absent instead of failing with an NPE.
+        assumeNotNull(System.getenv("BROWSERSTACK_ACCESS_KEY"));
         assertFalse(l.isRunning());
         l.start(options);
         assertTrue(l.isRunning());
     }
 
     @Test
     public void testMultipleBinary() throws Exception {
+        // Live integration test: starts real BrowserStack Local tunnels, so it
+        // requires a valid BROWSERSTACK_ACCESS_KEY (provided via CI secrets).
+        // Skip gracefully when the key is absent instead of failing with an NPE.
+        assumeNotNull(System.getenv("BROWSERSTACK_ACCESS_KEY"));
         l.start(options);
         assertTrue(l.isRunning());
         Local l2 = new Local();