Publish test-failure artifacts.

dist/azure-generic-build.yml

@@ -62,6 +62,22 @@ steps:
 - ${{ if parameters.testIt }}:
   - bash: cargo test --all --target $TARGET --release $CARGO_FEATURES_FLAGS --features="$CARGO_FEATURES_EXPLICIT"
     displayName: cargo test
+  - bash: |
+      artifact_dir="$(Build.ArtifactStagingDirectory)/test_failures"
+      mkdir -p "$artifact_dir"
+      mv *.observed "$artifact_dir"
+      mv *.expected "$artifact_dir"
+      if [ -n "$(ls -A $artifact_dir)" ]; then
+        echo "##vso[task.setvariable variable=TEST_FAILURE_ARTIFACTS;]true"
+      fi
+    displayName: Package test failure files
+    condition: failed()
+  - task: PublishPipelineArtifact@1
+    displayName: Publish packaged test failures
+    condition: eq(variables['TEST_FAILURE_ARTIFACTS'], true)
+    inputs:
+      targetPath: '$(Build.ArtifactStagingDirectory)/test_failures'
+      artifactName: test-failures-$(TARGET)
 
 # For non-canary builds, export artifacts.