In fuzzing add a final job verifying all the fuzz targets have been executed

.github/workflows/fuzz.yml

@@ -34,3 +34,20 @@ jobs:
       - run: echo "HFUZZ_RUN_ARGS=\"--run_time 30 --exit_upon_crash -v -f hfuzz_input/${{ matrix.fuzz_target }}/input\"" >> $GITHUB_ENV
       - name: fuzz
         run: cd fuzz && cargo +nightly hfuzz run ${{ matrix.fuzz_target }}
+      - run: echo "${{ matrix.fuzz_target }}.rs" >executed_${{ matrix.fuzz_target }}
+      - uses: actions/upload-artifact@v2
+        with:
+          name: executed_${{ matrix.fuzz_target }}
+          path: executed_${{ matrix.fuzz_target }}
+
+  verify-execution:
+    needs: fuzz
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/download-artifact@v2
+      - name: Display structure of downloaded files
+        run: ls -R
+      - run: find executed_* -type f -exec cat {} + | sort > executed
+      - run: ls fuzz/fuzz_targets | sort > expected
+      - run: diff expected executed