Add debugging info for Preconditions failure.

PiperOrigin-RevId: 363032442

src/main/java/com/google/devtools/build/lib/analysis/test/InstrumentedFileManifestAction.java

diff --git a/src/main/java/com/google/devtools/build/lib/analysis/test/InstrumentedFileManifestAction.java b/src/main/java/com/google/devtools/build/lib/analysis/test/InstrumentedFileManifestAction.java
index 001fbaf..2e689aa 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/test/InstrumentedFileManifestAction.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/test/InstrumentedFileManifestAction.java
@@ -99,7 +99,8 @@
   public static Artifact getInstrumentedFileManifest(RuleContext ruleContext,
       NestedSet<Artifact> additionalSourceFiles, NestedSet<Artifact> metadataFiles) {
     // Instrumented manifest makes sense only for rules with binary output.
-    Preconditions.checkState(ruleContext.getRule().hasBinaryOutput());
+    Preconditions.checkState(
+        ruleContext.getRule().hasBinaryOutput(), "not binary output: %s", ruleContext.getLabel());
     Artifact instrumentedFileManifest = ruleContext.getBinArtifact(
         ruleContext.getTarget().getName()  + ".instrumented_files");