try using travis env vars for password to key instead of the whole key

key.pem

@@ -0,0 +1,30 @@
+-----BEGIN RSA PRIVATE KEY-----
+Proc-Type: 4,ENCRYPTED
+DEK-Info: DES-EDE3-CBC,78E62ACC722BE51C
+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-----END RSA PRIVATE KEY-----

tests/Functional/AuthenticationTests.php

@@ -203,10 +203,10 @@ public function testAuthenticateViaOAuth2ClientCredentials()
         $state = $factory->newCollectionState();
 
         // Load the key
-        if(getenv('FS_CLIENT_KEY') === false){
-            throw new \Exception('Client key not set in FS_CLIENT_KEY environment variable');
+        if(getenv('FS_KEY_PASSWORD') === false){
+            throw new \Exception('Password for client key not set in FS_KEY_PASSWORD environment variable; unable to use key for authentication');
         }
-        $key = getenv('FS_CLIENT_KEY');
+        $key = openssl_pkey_get_private('file://key.pem', getenv('FS_KEY_PASSWORD'));
 
         $state->authenticateViaOAuth2ClientCredentials('a0T3000000BkhenEAB', $state->generateClientSecret($key, 1447773012436));