StatusConfigTest: Add test with empty value for disabled branch

This slightly increases the test coverage for StatusConfig from 98.3% to
100%.

Signed-off-by: Edwin Kempin <ekempin@google.com>
Change-Id: I833c490ca838b343efc986fe9b51c9d12cbb722f
diff --git a/java/com/google/gerrit/plugins/codeowners/backend/config/StatusConfig.java b/java/com/google/gerrit/plugins/codeowners/backend/config/StatusConfig.java
index bdc6e2f..720df22 100644
--- a/java/com/google/gerrit/plugins/codeowners/backend/config/StatusConfig.java
+++ b/java/com/google/gerrit/plugins/codeowners/backend/config/StatusConfig.java
@@ -18,6 +18,7 @@
 import static java.util.Objects.requireNonNull;
 
 import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableList;
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.entities.BranchNameKey;
@@ -215,7 +216,7 @@
   private boolean isDisabledForBranch(
       String[] refPatternList, String branch, String warningMsgForInvalidRefPattern) {
     for (String refPattern : refPatternList) {
-      if (refPattern == null) {
+      if (Strings.isNullOrEmpty(refPattern)) {
         continue;
       }
       try {
diff --git a/javatests/com/google/gerrit/plugins/codeowners/backend/config/StatusConfigTest.java b/javatests/com/google/gerrit/plugins/codeowners/backend/config/StatusConfigTest.java
index 8dc2a22..4163db3 100644
--- a/javatests/com/google/gerrit/plugins/codeowners/backend/config/StatusConfigTest.java
+++ b/javatests/com/google/gerrit/plugins/codeowners/backend/config/StatusConfigTest.java
@@ -125,6 +125,14 @@
   }
 
   @Test
+  public void isDisabledForBranchForConfigWithEmptyValue() throws Exception {
+    Config cfg = new Config();
+    cfg.setStringList(SECTION_CODE_OWNERS, null, KEY_DISABLED_BRANCH, ImmutableList.of(""));
+    assertThat(statusConfig.isDisabledForBranch(cfg, BranchNameKey.create(project, "master")))
+        .isFalse();
+  }
+
+  @Test
   public void isDisabledForBranch_exactRef() throws Exception {
     Config cfg = new Config();
     cfg.setStringList(