Some more cleanup.

--
MOS_MIGRATED_REVID=87942730
diff --git a/src/test/java/com/google/devtools/build/lib/util/ResourceFileLoaderTest.java b/src/test/java/com/google/devtools/build/lib/util/ResourceFileLoaderTest.java
index e821ca1..6067101 100644
--- a/src/test/java/com/google/devtools/build/lib/util/ResourceFileLoaderTest.java
+++ b/src/test/java/com/google/devtools/build/lib/util/ResourceFileLoaderTest.java
@@ -13,6 +13,7 @@
 // limitations under the License.
 package com.google.devtools.build.lib.util;
 
+import static com.google.common.truth.Truth.assertThat;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.fail;
 
@@ -42,7 +43,7 @@
           "does_not_exist.txt");
       fail();
     } catch (IOException e) {
-      assertEquals("does_not_exist.txt not found.", e.getMessage());
+      assertThat(e).hasMessage("does_not_exist.txt not found.");
     }
   }