Add environment variable support for Go tests

[Eric-Arellano]

With Python, we support setting env variables two ways:

1. [test].extra_env_vars
2. the extra_env_vars field

Neither is hooked up for Go, which is pure oversight.

Hook up [test].extra_env_vars

1. Request TestExtraEnv in the @rule signature

pants/src/python/pants/backend/go/goals/test.py

Lines 149 to 152 in bf25e12

	@rule(desc="Test with Go", level=LogLevel.DEBUG)
	async def run_go_tests(
	field_set: GoTestFieldSet, test_subsystem: TestSubsystem, go_test_subsystem: GoTestSubsystem
	) -> TestResult:

Like this:

pants/src/python/pants/backend/python/goals/pytest_runner.py

Lines 167 to 177 in 209b354

	@rule(level=LogLevel.DEBUG)
	async def setup_pytest_for_target(
	request: TestSetupRequest,
	pytest: PyTest,
	test_subsystem: TestSubsystem,
	python_setup: PythonSetup,
	coverage_config: CoverageConfig,
	coverage_subsystem: CoverageSubsystem,
	test_extra_env: TestExtraEnv,
	global_options: GlobalOptions,
	) -> TestSetup:

2. Set the Process's env field to test_extra_env.env

https://github.com/pantsbuild/pants/blob/bf25e129288e80116220292786f7e6018184173e/src/python/pants/backend/go/goals/test.py#L311-L234

3. Add a test to test_test.py, e.g.
   

   pants/src/python/pants/backend/python/goals/pytest_runner_integration_test.py

   Lines 402 to 443 in 209b354

   	def test_extra_env_vars(rule_runner: RuleRunner) -> None:
   	rule_runner.write_files(
   	{
   	f"{PACKAGE}/test_extra_env_vars.py": dedent(
   	"""\
   	import os
   	def test_args():
   	assert os.getenv("ARG_WITH_VALUE_VAR") == "arg_with_value_var"
   	assert os.getenv("ARG_WITHOUT_VALUE_VAR") == "arg_without_value_value"
   	assert os.getenv("PYTHON_TESTS_VAR_WITH_VALUE") == "python_tests_var_with_value"
   	assert os.getenv("PYTHON_TESTS_VAR_WITHOUT_VALUE") == "python_tests_var_without_value"
   	assert os.getenv("PYTHON_TESTS_OVERRIDE_WITH_VALUE_VAR") == "python_tests_override_with_value_var_override"
   	"""
   	),
   	f"{PACKAGE}/BUILD": dedent(
   	"""\
   	python_tests(
   	extra_env_vars=(
   	"PYTHON_TESTS_VAR_WITHOUT_VALUE",
   	"PYTHON_TESTS_VAR_WITH_VALUE=python_tests_var_with_value",
   	"PYTHON_TESTS_OVERRIDE_WITH_VALUE_VAR=python_tests_override_with_value_var_override",
   	)
   	)
   	"""
   	),
   	}
   	)
   	tgt = rule_runner.get_target(Address(PACKAGE, relative_file_path="test_extra_env_vars.py"))
   	result = run_pytest(
   	rule_runner,
   	tgt,
   	extra_args=[
   	'--test-extra-env-vars=["ARG_WITH_VALUE_VAR=arg_with_value_var", "ARG_WITHOUT_VALUE_VAR", "PYTHON_TESTS_OVERRIDE_ARG_WITH_VALUE_VAR"]'
   	],
   	env={
   	"ARG_WITHOUT_VALUE_VAR": "arg_without_value_value",
   	"PYTHON_TESTS_VAR_WITHOUT_VALUE": "python_tests_var_without_value",
   	"PYTHON_TESTS_OVERRIDE_WITH_VALUE_VAR": "python_tests_override_with_value_var",
   	},
   	)
   	assert result.exit_code == 0

Add field

1. Register new field to go_package target, probably called test_extra_env_vars. See this for example:

pants/src/python/pants/backend/python/target_types.py

Lines 811 to 820 in 209b354

	class PythonTestsExtraEnvVarsField(StringSequenceField):
	alias = "extra_env_vars"
	help = softwrap(
	"""
	Additional environment variables to include in test processes.
	Entries are strings in the form `ENV_VAR=value` to use explicitly; or just
	`ENV_VAR` to copy the value of a variable in Pants's own environment.
	This will be merged with and override values from [test].extra_env_vars.
	"""
	)

https://www.pantsbuild.org/docs/target-api for general docs on Target API

2. Consume in the rule, like this:

pants/src/python/pants/backend/python/goals/pytest_runner.py

Lines 210 to 212 in 209b354

	field_set_extra_env_get = Get(
	Environment, EnvironmentRequest(request.field_set.extra_env_vars.value or ())
	)

pants/src/python/pants/backend/python/goals/pytest_runner.py

Lines 315 to 322 in 209b354

	extra_env = {
	"PYTEST_ADDOPTS": " ".join(add_opts),
	"PEX_EXTRA_SYS_PATH": ":".join(prepared_sources.source_roots),
	**test_extra_env.env,
	# NOTE: field_set_extra_env intentionally after `test_extra_env` to allow overriding within
	# `python_tests`.
	**field_set_extra_env,
	}

(You have to update the FieldSet to have the field)

3. Update the test from before so that you test the field too, including that the field overrides the option.

[wfscheper]

I just ran into this trying out pants with a personal project. Mind if I try my hand at a PR?

[Eric-Arellano]

Please go for it, @wfscheper! Let me know if you have questions. If you're not yet on it, we're a friendly bunch on Slack :) https://www.pantsbuild.org/docs/getting-help

[tdyas]

Closing since this was already implemented by #16013.