Add e2e Tests

**Description of the problem / feature request:**

We should add some e2e tests. Something like what Bazel has https://github.com/bazelbuild/bazel/tree/master/src/test/shell

**Feature requests: what underlying problem are you trying to solve with this feature?**

To make sure the tool works properly end-to-end.

Start by reviewing the Bazel shell test examples linked in the issue and the bazel-bench repository structure to find the tool’s executable entry point and existing test setup. Define an end-to-end test approach that exercises the tool as a user would; done means a repeatable suite verifies that the tool works end to end.

Written by the indexing model from the issue text.