Run and Debug Unit Tests with Flags: Tackling Conflicting Protobuf Extensions

While debugging unit tests within VS Code, it may be necessary to pass additional flags to account for conflicting Protobuf extensions. This guide provides a solution to this issue, allowing for seamless debugging.

The original configuration in VS Code settings.json attempts to add the required flag '-ldflags "-X google.golang.org/protobuf/reflect/protoregistry.conflictPolicy=warn"'. However, this configuration faces an issue when VS Code generates a test command with single quotes around the flag.

To resolve this, an adjustment to the configuration in settings.json is required. The modification should remove the single quotes from around the flag value:

"go.testFlags": [
    "-ldflags",
    "-X google.golang.org/protobuf/reflect/protoregistry.conflictPolicy=warn"
]

With this modification, VS Code will generate a test command that properly includes the necessary flag without causing the error associated with proto extension conflicts.

For debugging, a different approach is recommended due to the complexities of debugging specific tests using the VS Code interface. Compiling the test binary with specific flags and utilizing dlv for headless debugging allows for greater control and efficient debugging.

To compile the test binary:

go test -c -ldflags "-X google.golang.org/protobuf/reflect/protoregistry.conflictPolicy=warn" -gcflags="all=-N -l"

This command generates a binary with the required flags for debugging. To connect dlv in headless mode for editor connection:

dlv exec ./foo.test --headless --listen=:2345 --log --api-version=2 -- -count=1 -- $(pwd)/some/path

Here, foo.test is the generated binary, -count=1 represents custom flags for testing, and $(pwd)/some/path can be used for cucumber-style tests. Connect your editor to the dlv session and start debugging.

Additional Information

Go also provides convenient methods for launching dlv through inline flags, and for Vim users, the vim-go plugin allows for custom breakpoint setting and dlv connection using commands like :GoDebugConnect 127.0.0.1:2345. By following the steps outlined above, developers can effectively run and debug unit tests with flags, ensuring smooth testing and code maintenance.