test(f1): assert configuration precedence and behavior

Restructure configuration tests to eliminate env-mutation from
options_test.go:

- Move TestEnvVarsUsedByDefault to f1_test.go (already exempted from
  paralleltest for signal testing)
- Remove env-mutation tests now redundant with WithSettings-based tests
- All options_test.go tests now call t.Parallel
- Remove golangci.yml paralleltest exclusion for options_test.go

Add precedence assertion tests:
- TestWithSettingsOverridesFinegrained: WithSettings placed last wins
- TestWithLoggerTakesPrecedenceOverWithSettings: WithLogger overrides
  Settings logging config
- TestWithSettingsAllFields: all Settings fields flow through correctly
- TestWithSettingsEmptyDisablesAllSettings: zero-value baseline

Author: nvloff-f3

.golangci.yml

@@ -85,9 +85,6 @@ linters:
       # cobra.AddTemplateFunc modifies a global map; sync.Once is required
       - linters: [gochecknoglobals]
         path: internal/run/help\.go
-      # t.Setenv is incompatible with t.Parallel (Go constraint)
-      - linters: [paralleltest, tparallel]
-        path: options_test\.go
       - linters: [staticcheck]
         path: _test\.go
         text: ST1003

docs/CODEBASE_REVIEW.md

@@ -51,7 +51,7 @@
 - **Public types:** `Settings`, `PrometheusSettings`, `LoggingSettings`, `LogFormat` (strongly typed, no string-key API). `DefaultSettings()` loads from env vars.
 - **Scenarios:** `WithDescription`, `WithParameter`; `Scenario.RunFn` populated by framework during setup.
 - **f1testing.T:** `NewTWithOptions(scenarioName, ...TOption)`; `WithLogger`, `WithIteration`, `WithVUID`; `Error`/`Fatal`/`Log` with `args ...any` (testing.T compatible).
-- **Options:** All consolidated in `options.go`; types in `settings.go`. Precedence: programmatic options > env vars > defaults. `WithLogger` takes precedence over log level/format options.
+- **Options:** All consolidated in `options.go`; types in `settings.go`. Precedence: programmatic options > env vars > defaults. `WithLogger` takes precedence over log level/format options. All configuration tests are parallel (no env mutation in options_test.go); env backward-compat test lives in f1_test.go with signal tests.
 - **Design decisions:** No `Config` struct (bundles unrelated concerns), no `SettingsProvider` (lazy eval adds no benefit). `WithSettings(Settings{})` replaces `WithoutEnvSettings()` — explicit, no order-dependence. Typed logging APIs (`slog.Level`, `LogFormat`) instead of strings. `ParseLogLevel`/`ParseLogFormat` helpers for users who need string-to-type conversion (e.g., from config files); validation lives inside f1.
 
 ### Suggested Improvements

pkg/f1/f1_test.go

@@ -5,6 +5,8 @@ import (
 	"syscall"
 	"testing"
 	"time"
+
+	"github.com/stretchr/testify/require"
 )
 
 func TestSignalHandling(t *testing.T) {
@@ -46,6 +48,17 @@ func TestMissingScenario(t *testing.T) {
 		the_execute_command_returns_an_error("scenario not defined: unknownScenario")
 }
 
+func TestEnvVarsUsedByDefault(t *testing.T) {
+	ts, count := newPushGatewayServer(t)
+	t.Setenv("PROMETHEUS_PUSH_GATEWAY", ts.URL)
+
+	inst := newF1WithScenario("env_default")
+	runConstant(t, inst, "env_default")
+
+	require.Positive(t, count.Load(),
+		"PROMETHEUS_PUSH_GATEWAY env var should trigger metrics push")
+}
+
 func TestWithCustomLogger(t *testing.T) {
 	given, when, then := newF1Stage(t)
 

pkg/f1/options_test.go

@@ -49,17 +49,6 @@ func runConstant(t *testing.T, inst *f1.F1, scenario string) {
 	require.NoError(t, err)
 }
 
-func TestEnvVarsUsedByDefault(t *testing.T) {
-	ts, count := newPushGatewayServer(t)
-	t.Setenv("PROMETHEUS_PUSH_GATEWAY", ts.URL)
-
-	inst := newF1WithScenario("env_default")
-	runConstant(t, inst, "env_default")
-
-	require.Positive(t, count.Load(),
-		"PROMETHEUS_PUSH_GATEWAY env var should trigger metrics push")
-}
-
 func TestWithSettingsReplacesPushGateway(t *testing.T) {
 	t.Parallel()
 
@@ -75,26 +64,17 @@ func TestWithSettingsReplacesPushGateway(t *testing.T) {
 		"WithSettings should configure push gateway without env vars")
 }
 
-func TestWithSettingsEmptyIgnoresEnvVars(t *testing.T) {
-	ts, count := newPushGatewayServer(t)
-	t.Setenv("PROMETHEUS_PUSH_GATEWAY", ts.URL)
-
-	inst := newF1WithScenario("no_env", f1.WithSettings(f1.Settings{}))
-	runConstant(t, inst, "no_env")
-
-	require.Equal(t, int32(0), count.Load(),
-		"WithSettings(Settings{}) should ignore env vars")
-}
+func TestWithSettingsEmptyDisablesAllSettings(t *testing.T) {
+	t.Parallel()
 
-func TestWithPrometheusPushGatewayOverridesEnv(t *testing.T) {
 	ts, count := newPushGatewayServer(t)
-	t.Setenv("PROMETHEUS_PUSH_GATEWAY", "http://env-should-not-be-used.invalid")
+	_ = ts
 
-	inst := newF1WithScenario("override", f1.WithPrometheusPushGateway(ts.URL))
-	runConstant(t, inst, "override")
+	inst := newF1WithScenario("empty_settings", f1.WithSettings(f1.Settings{}))
+	runConstant(t, inst, "empty_settings")
 
-	require.Positive(t, count.Load(),
-		"WithPrometheusPushGateway should override env var")
+	require.Equal(t, int32(0), count.Load(),
+		"WithSettings(Settings{}) should start from zero values; no push gateway")
 }
 
 func TestFineGrainedOverridesAfterWithSettings(t *testing.T) {
@@ -111,6 +91,21 @@ func TestFineGrainedOverridesAfterWithSettings(t *testing.T) {
 		"fine-grained options should apply after WithSettings")
 }
 
+func TestWithSettingsOverridesFinegrained(t *testing.T) {
+	t.Parallel()
+
+	ts, count := newPushGatewayServer(t)
+
+	inst := newF1WithScenario("settings_last",
+		f1.WithPrometheusPushGateway(ts.URL),
+		f1.WithSettings(f1.Settings{}),
+	)
+	runConstant(t, inst, "settings_last")
+
+	require.Equal(t, int32(0), count.Load(),
+		"WithSettings placed after fine-grained options should replace them")
+}
+
 func TestWithLogLevelAndFormat(t *testing.T) {
 	t.Parallel()
 
@@ -141,35 +136,50 @@ func TestWithLoggerTakesPrecedenceOverLogOptions(t *testing.T) {
 		"explicit logger format (text) should be used, not JSON from WithLogFormat")
 }
 
-func TestDefaultSettingsLoadsEnv(t *testing.T) {
-	t.Setenv("PROMETHEUS_PUSH_GATEWAY", "http://test:9091")
-	t.Setenv("PROMETHEUS_NAMESPACE", "test-ns")
-	t.Setenv("PROMETHEUS_LABEL_ID", "test-id")
-	t.Setenv("LOG_FILE_PATH", "/tmp/test.log")
-	t.Setenv("F1_LOG_LEVEL", "debug")
-	t.Setenv("F1_LOG_FORMAT", "json")
-
-	s := f1.DefaultSettings()
-	require.Equal(t, "http://test:9091", s.Prometheus.PushGateway)
-	require.Equal(t, "test-ns", s.Prometheus.Namespace)
-	require.Equal(t, "test-id", s.Prometheus.LabelID)
-	require.Equal(t, "/tmp/test.log", s.Logging.FilePath)
-	require.Equal(t, slog.LevelDebug, s.Logging.Level)
-	require.Equal(t, f1.LogFormatJSON, s.Logging.Format)
-}
-
-func TestDefaultSettingsReturnsDefaults(t *testing.T) {
-	t.Setenv("PROMETHEUS_PUSH_GATEWAY", "")
-	t.Setenv("PROMETHEUS_NAMESPACE", "")
-	t.Setenv("PROMETHEUS_LABEL_ID", "")
-	t.Setenv("LOG_FILE_PATH", "")
-	t.Setenv("F1_LOG_LEVEL", "")
-	t.Setenv("F1_LOG_FORMAT", "")
-
-	s := f1.DefaultSettings()
-	require.Empty(t, s.Prometheus.PushGateway)
-	require.Equal(t, slog.LevelInfo, s.Logging.Level)
-	require.Equal(t, f1.LogFormatText, s.Logging.Format)
+func TestWithLoggerTakesPrecedenceOverWithSettings(t *testing.T) {
+	t.Parallel()
+
+	var buf bytes.Buffer
+	logger := log.NewTestLogger(&buf)
+
+	inst := newF1WithScenario("logger_over_settings",
+		f1.WithSettings(f1.Settings{
+			Logging: f1.LoggingSettings{
+				Level:  slog.LevelError,
+				Format: f1.LogFormatJSON,
+			},
+		}),
+		f1.WithLogger(logger),
+	)
+	runConstant(t, inst, "logger_over_settings")
+
+	output := buf.String()
+	require.NotEmpty(t, output, "WithLogger should capture output")
+	require.NotContains(t, output, `"level"`,
+		"WithLogger text format should override Settings JSON format")
+}
+
+func TestWithSettingsAllFields(t *testing.T) {
+	t.Parallel()
+
+	ts, count := newPushGatewayServer(t)
+	inst := newF1WithScenario("all_fields",
+		f1.WithSettings(f1.Settings{
+			Prometheus: f1.PrometheusSettings{
+				PushGateway: ts.URL,
+				Namespace:   "test-ns",
+				LabelID:     "test-id",
+			},
+			Logging: f1.LoggingSettings{
+				Level:  slog.LevelDebug,
+				Format: f1.LogFormatJSON,
+			},
+		}),
+	)
+	runConstant(t, inst, "all_fields")
+
+	require.Positive(t, count.Load(),
+		"WithSettings with PushGateway should trigger metrics push")
 }
 
 func TestParseLogLevel(t *testing.T) {