Fix Travis build

 - Add static creds in test client to bypass the default credentials chain
 - Suppress false positive bug

Author: dagnir

build-tools/src/main/resources/software/amazon/awssdk/spotbugs-suppressions.xml

@@ -172,6 +172,14 @@
         <Bug pattern="RCN_REDUNDANT_NULLCHECK_OF_NONNULL_VALUE"/>
     </Match>
 
+    <!-- See SpotBugs bug: https://github.com/spotbugs/spotbugs/issues/600, https://github.com/spotbugs/spotbugs/issues/756 -->
+    <Match>
+        <Class name="software.amazon.awssdk.codegen.emitters.CodeWriter"/>
+        <Method name="flush"/>
+        <Bug pattern="RCN_REDUNDANT_NULLCHECK_OF_NONNULL_VALUE"/>
+    </Match>
+
+
     <!-- If we're not sure about the RV_RETURN_VALUE_IGNORED_NO_SIDE_EFFECT, skip the warning. -->
     <Match>
         <Package name="~software.amazon.awssdk.http.nio.netty.*"/>

test/codegen-generated-classes-test/src/test/java/software/amazon/awssdk/services/EndpointDiscoveryAndEndpointOverrideTest.java

@@ -15,6 +15,8 @@
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.Parameterized;
+import software.amazon.awssdk.auth.credentials.AwsBasicCredentials;
+import software.amazon.awssdk.auth.credentials.StaticCredentialsProvider;
 import software.amazon.awssdk.awscore.client.builder.AwsClientBuilder;
 import software.amazon.awssdk.core.client.builder.SdkClientBuilder;
 import software.amazon.awssdk.core.exception.SdkClientException;
@@ -172,6 +174,7 @@ private static List<TestCase<?>> endpointDiscoveryRequiredAndCustomizedCases(boo
     private static <T> T createClient(AwsClientBuilder<?, T> clientBuilder,
                                       boolean endpointOverridden) {
         return clientBuilder.region(Region.US_WEST_2)
+                            .credentialsProvider(StaticCredentialsProvider.create(AwsBasicCredentials.create("akid", "skid")))
                             .applyMutation(c -> addEndpointOverride(c, endpointOverridden))
                             .overrideConfiguration(c -> c.retryPolicy(p -> p.numRetries(0))
                                                          .addExecutionInterceptor(new EndpointCapturingInterceptor()))