test: speed up (#1121)

Full suite 178s → 96s, and a run's log 12MB → 2KB. `act/runner` was 177s of the 178s, serialised behind one docker daemon.

- Its fixtures now run in parallel, bounded by a slot count instead of `go test -parallel`, with a per-test container name prefix and a pinned `MaxParallel`.
- Fixtures asserting a job failure leaked their container and network (`AutoRemove` was at the act-CLI default), filling the daemon's address pool over time.
- Replaced sleeps used as synchronisation in the parallel-executor and cache-handler tests.
- Dropped duplicate coverage: two files re-testing `NewParallelExecutor`, a test asserting on its own semaphore, and `TestDockerActionForcePullForceRebuild`, whose config `runTest` discarded.
- `fmt-check`/`security-check` move from `make test` to a `checks` target; `security-check` no longer installs `xgo` and `gxz`.
- Test flags follow gitea: `GOTEST_FLAGS ?= -race -timeout 20m -parallel 8`, with `-cover`/`-coverprofile` left in the target. Dropped `-v`, since a failing package still prints its full output without it.

Coverage unchanged at 73.4%.

Reviewed-on: https://gitea.com/gitea/runner/pulls/1121
Reviewed-by: bircni <bircni@icloud.com>
Co-authored-by: silverwind <me@silverwind.io>

.gitea/workflows/test.yml

@@ -33,6 +33,8 @@ jobs:
           done
       - name: lint
         run: make lint
+      - name: checks
+        run: make checks
       - name: build
         run: make build
       - name: test

Makefile

@@ -21,6 +21,8 @@ DOCKER_ROOTLESS_REF := $(DOCKER_IMAGE):$(DOCKER_TAG)-dind-rootless
 GOLANGCI_LINT_PACKAGE ?= github.com/golangci/golangci-lint/v2/cmd/golangci-lint@v2.12.2
 GOVULNCHECK_PACKAGE ?= golang.org/x/vuln/cmd/govulncheck@v1.3.0
 
+GOTEST_FLAGS ?= -race -timeout 20m -parallel 8
+
 STATIC ?=
 EXTLDFLAGS ?=
 ifneq ($(STATIC),)
@@ -110,6 +112,9 @@ deps-tools: ## install tool dependencies
 	$(GO) install $(GOVULNCHECK_PACKAGE) & \
 	wait
 
+.PHONY: checks
+checks: tidy-check fmt-check security-check ## run the non-lint source checks
+
 .PHONY: lint
 lint: lint-go lint-go-windows ## lint everything
 
@@ -131,7 +136,7 @@ lint-pr-title: ## lint PR title against Conventional Commits (set PR_TITLE=...)
 	@node ./tools/lint-pr-title.ts
 
 .PHONY: security-check
-security-check: deps-tools
+security-check:
 	GOEXPERIMENT= $(GO) run $(GOVULNCHECK_PACKAGE) -show color ./... || true
 
 .PHONY: tidy
@@ -148,8 +153,8 @@ tidy-check: tidy
 	fi
 
 .PHONY: test
-test: fmt-check security-check ## test everything (integration tests self-skip without docker/network)
-	@$(GO) test -race -timeout 20m -v -cover -coverprofile coverage.txt ./... && echo "\n==>\033[32m Ok\033[m\n" || exit 1
+test: ## test everything (integration tests self-skip without docker/network)
+	@$(GO) test $(GOTEST_FLAGS) -cover -coverprofile coverage.txt ./... && echo "\n==>\033[32m Ok\033[m\n" || exit 1
 
 .PHONY: coverage-report
 coverage-report: ## turn coverage.txt from `make test` into .tmp/coverage.md

act/artifactcache/handler_test.go

@@ -445,13 +445,6 @@ func TestHandler(t *testing.T) {
 		require.Equal(t, 404, resp.StatusCode)
 	})
 
-	t.Run("get with not exist id", func(t *testing.T) {
-		resp, err := testClient.Get(signArtifactURL(handler, 100))
-		require.NoError(t, err)
-		defer resp.Body.Close()
-		require.Equal(t, 404, resp.StatusCode)
-	})
-
 	t.Run("get with multiple keys", func(t *testing.T) {
 		version := "c19da02a2bd7e77277f1ac29ab45c09b7d46a4ee758284e26bb3045ad11d9d20"
 		key := strings.ToLower(t.Name())
@@ -469,7 +462,8 @@ func TestHandler(t *testing.T) {
 			_, err := rand.Read(contents[i])
 			require.NoError(t, err)
 			uploadCacheNormally(t, base, keys[i], version, contents[i])
-			time.Sleep(time.Second) // ensure CreatedAt of caches are different
+			// ensure CreatedAt of caches are different, in upload order
+			backdateCache(t, handler, keys[i], time.Duration(len(contents)-i)*time.Second)
 		}
 
 		reqKeys := strings.Join([]string{
@@ -554,7 +548,8 @@ func TestHandler(t *testing.T) {
 			_, err := rand.Read(contents[i])
 			require.NoError(t, err)
 			uploadCacheNormally(t, base, keys[i], version, contents[i])
-			time.Sleep(time.Second) // ensure CreatedAt of caches are different
+			// ensure CreatedAt of caches are different, in upload order
+			backdateCache(t, handler, keys[i], time.Duration(len(contents)-i)*time.Second)
 		}
 
 		reqKeys := strings.Join([]string{
@@ -607,7 +602,8 @@ func TestHandler(t *testing.T) {
 			_, err := rand.Read(contents[i])
 			require.NoError(t, err)
 			uploadCacheNormally(t, base, keys[i], version, contents[i])
-			time.Sleep(time.Second) // ensure CreatedAt of caches are different
+			// ensure CreatedAt of caches are different, in upload order
+			backdateCache(t, handler, keys[i], time.Duration(len(contents)-i)*time.Second)
 		}
 
 		reqKeys := strings.Join([]string{
@@ -646,6 +642,20 @@ func TestHandler(t *testing.T) {
 	})
 }
 
+// backdateCache rewrites a cache's CreatedAt. It has one-second resolution, so age-ordering
+// tests set it directly instead of sleeping a second between uploads.
+func backdateCache(t *testing.T, handler *Handler, key string, age time.Duration) {
+	db, err := handler.openDB()
+	require.NoError(t, err)
+	defer db.Close()
+
+	var caches []*Cache
+	require.NoError(t, db.Find(&caches, bolthold.Where("Key").Eq(key)))
+	require.Len(t, caches, 1)
+	caches[0].CreatedAt = time.Now().Add(-age).Unix()
+	require.NoError(t, db.Update(caches[0].ID, caches[0]))
+}
+
 func uploadCacheNormally(t *testing.T, base, key, version string, content []byte) { //nolint:unparam // pre-existing issue from nektos/act
 	var id uint64
 	{

act/common/executor_max_parallel_test.go

@@ -1,89 +0,0 @@
-// Copyright 2026 The Gitea Authors. All rights reserved.
-// SPDX-License-Identifier: MIT
-
-package common
-
-import (
-	"context"
-	"sync"
-	"sync/atomic"
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/assert"
-)
-
-// Simple fast test that verifies max-parallel: 2 limits concurrency
-func TestMaxParallel2Quick(t *testing.T) {
-	ctx := context.Background()
-
-	var currentRunning atomic.Int32
-	var maxSimultaneous atomic.Int32
-
-	executors := make([]Executor, 4)
-	for i := range 4 {
-		executors[i] = func(ctx context.Context) error {
-			current := currentRunning.Add(1)
-
-			// Update max if needed
-			for {
-				maxValue := maxSimultaneous.Load()
-				if current <= maxValue || maxSimultaneous.CompareAndSwap(maxValue, current) {
-					break
-				}
-			}
-
-			time.Sleep(10 * time.Millisecond)
-			currentRunning.Add(-1)
-			return nil
-		}
-	}
-
-	err := NewParallelExecutor(2, executors...)(ctx)
-
-	assert.NoError(t, err) //nolint:testifylint // pre-existing issue from nektos/act
-	assert.LessOrEqual(t, maxSimultaneous.Load(), int32(2),
-		"Should not exceed max-parallel: 2")
-}
-
-// Test that verifies max-parallel: 1 enforces sequential execution
-func TestMaxParallel1Sequential(t *testing.T) {
-	ctx := context.Background()
-
-	var currentRunning atomic.Int32
-	var maxSimultaneous atomic.Int32
-	var executionOrder []int
-	var orderMutex sync.Mutex
-
-	executors := make([]Executor, 5)
-	for i := range 5 {
-		taskID := i
-		executors[i] = func(ctx context.Context) error {
-			current := currentRunning.Add(1)
-
-			// Track execution order
-			orderMutex.Lock()
-			executionOrder = append(executionOrder, taskID)
-			orderMutex.Unlock()
-
-			// Update max if needed
-			for {
-				maxValue := maxSimultaneous.Load()
-				if current <= maxValue || maxSimultaneous.CompareAndSwap(maxValue, current) {
-					break
-				}
-			}
-
-			time.Sleep(20 * time.Millisecond)
-			currentRunning.Add(-1)
-			return nil
-		}
-	}
-
-	err := NewParallelExecutor(1, executors...)(ctx)
-
-	assert.NoError(t, err) //nolint:testifylint // pre-existing issue from nektos/act
-	assert.Equal(t, int32(1), maxSimultaneous.Load(),
-		"max-parallel: 1 should only run 1 task at a time")
-	assert.Len(t, executionOrder, 5, "All 5 tasks should have executed")
-}

act/common/executor_parallel_advanced_test.go

@@ -1,221 +0,0 @@
-// Copyright 2026 The Gitea Authors. All rights reserved.
-// SPDX-License-Identifier: MIT
-
-package common
-
-import (
-	"context"
-	"sync"
-	"sync/atomic"
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/assert"
-)
-
-// TestMaxParallelJobExecution tests actual job execution with max-parallel
-func TestMaxParallelJobExecution(t *testing.T) {
-	t.Run("MaxParallel=1 Sequential", func(t *testing.T) {
-		var currentRunning atomic.Int32
-		var maxConcurrent int32
-		var executionOrder []int
-		var mu sync.Mutex
-
-		executors := make([]Executor, 5)
-		for i := range 5 {
-			taskID := i
-			executors[i] = func(ctx context.Context) error {
-				current := currentRunning.Add(1)
-
-				// Track max concurrent
-				for {
-					maxValue := atomic.LoadInt32(&maxConcurrent)
-					if current <= maxValue || atomic.CompareAndSwapInt32(&maxConcurrent, maxValue, current) {
-						break
-					}
-				}
-
-				mu.Lock()
-				executionOrder = append(executionOrder, taskID)
-				mu.Unlock()
-
-				time.Sleep(10 * time.Millisecond)
-				currentRunning.Add(-1)
-				return nil
-			}
-		}
-
-		ctx := context.Background()
-		err := NewParallelExecutor(1, executors...)(ctx)
-		assert.NoError(t, err) //nolint:testifylint // pre-existing issue from nektos/act
-
-		assert.Equal(t, int32(1), maxConcurrent, "Should never exceed 1 concurrent execution")
-		assert.Len(t, executionOrder, 5, "All tasks should execute")
-	})
-
-	t.Run("MaxParallel=3 Limited", func(t *testing.T) {
-		var currentRunning atomic.Int32
-		var maxConcurrent int32
-
-		executors := make([]Executor, 10)
-		for i := range 10 {
-			executors[i] = func(ctx context.Context) error {
-				current := currentRunning.Add(1)
-
-				for {
-					maxValue := atomic.LoadInt32(&maxConcurrent)
-					if current <= maxValue || atomic.CompareAndSwapInt32(&maxConcurrent, maxValue, current) {
-						break
-					}
-				}
-
-				time.Sleep(20 * time.Millisecond)
-				currentRunning.Add(-1)
-				return nil
-			}
-		}
-
-		ctx := context.Background()
-		err := NewParallelExecutor(3, executors...)(ctx)
-		assert.NoError(t, err) //nolint:testifylint // pre-existing issue from nektos/act
-
-		assert.LessOrEqual(t, int(maxConcurrent), 3, "Should never exceed 3 concurrent executions")
-		assert.GreaterOrEqual(t, int(maxConcurrent), 1, "Should have at least 1 concurrent execution")
-	})
-
-	t.Run("MaxParallel=0 Uses1Worker", func(t *testing.T) {
-		var maxConcurrent int32
-		var currentRunning atomic.Int32
-
-		executors := make([]Executor, 5)
-		for i := range 5 {
-			executors[i] = func(ctx context.Context) error {
-				current := currentRunning.Add(1)
-
-				for {
-					maxValue := atomic.LoadInt32(&maxConcurrent)
-					if current <= maxValue || atomic.CompareAndSwapInt32(&maxConcurrent, maxValue, current) {
-						break
-					}
-				}
-
-				time.Sleep(10 * time.Millisecond)
-				currentRunning.Add(-1)
-				return nil
-			}
-		}
-
-		ctx := context.Background()
-		// When maxParallel is 0 or negative, it defaults to 1
-		err := NewParallelExecutor(0, executors...)(ctx)
-		assert.NoError(t, err) //nolint:testifylint // pre-existing issue from nektos/act
-
-		assert.Equal(t, int32(1), maxConcurrent, "Should use 1 worker when max-parallel is 0")
-	})
-}
-
-// TestMaxParallelWithErrors tests error handling with max-parallel
-func TestMaxParallelWithErrors(t *testing.T) {
-	t.Run("OneTaskFailsOthersContinue", func(t *testing.T) {
-		var successCount int32
-
-		executors := make([]Executor, 5)
-		for i := range 5 {
-			taskID := i
-			executors[i] = func(ctx context.Context) error {
-				if taskID == 2 {
-					return assert.AnError
-				}
-				atomic.AddInt32(&successCount, 1)
-				return nil
-			}
-		}
-
-		ctx := context.Background()
-		err := NewParallelExecutor(2, executors...)(ctx)
-
-		// Should return the error from task 2
-		assert.Error(t, err) //nolint:testifylint // pre-existing issue from nektos/act
-
-		// Other tasks should still execute
-		assert.Equal(t, int32(4), successCount, "4 tasks should succeed")
-	})
-
-	t.Run("ContextCancellation", func(t *testing.T) {
-		ctx, cancel := context.WithCancel(context.Background())
-
-		var startedCount int32
-		executors := make([]Executor, 10)
-		for i := range 10 {
-			executors[i] = func(ctx context.Context) error {
-				atomic.AddInt32(&startedCount, 1)
-				time.Sleep(100 * time.Millisecond)
-				return nil
-			}
-		}
-
-		// Cancel after a short delay
-		go func() {
-			time.Sleep(30 * time.Millisecond)
-			cancel()
-		}()
-
-		err := NewParallelExecutor(3, executors...)(ctx)
-		assert.Error(t, err)                     //nolint:testifylint // pre-existing issue from nektos/act
-		assert.ErrorIs(t, err, context.Canceled) //nolint:testifylint // pre-existing issue from nektos/act
-
-		// Not all tasks should start due to cancellation (but timing may vary)
-		// Just verify cancellation occurred
-		t.Logf("Started %d tasks before cancellation", startedCount)
-	})
-}
-
-// TestMaxParallelResourceSharing tests resource sharing scenarios
-func TestMaxParallelResourceSharing(t *testing.T) {
-	t.Run("SharedResourceWithMutex", func(t *testing.T) {
-		var sharedCounter int
-		var mu sync.Mutex
-
-		executors := make([]Executor, 100)
-		for i := range 100 {
-			executors[i] = func(ctx context.Context) error {
-				mu.Lock()
-				sharedCounter++
-				mu.Unlock()
-				return nil
-			}
-		}
-
-		ctx := context.Background()
-		err := NewParallelExecutor(10, executors...)(ctx)
-		assert.NoError(t, err) //nolint:testifylint // pre-existing issue from nektos/act
-
-		assert.Equal(t, 100, sharedCounter, "All tasks should increment counter")
-	})
-
-	t.Run("ChannelCommunication", func(t *testing.T) {
-		resultChan := make(chan int, 50)
-
-		executors := make([]Executor, 50)
-		for i := range 50 {
-			taskID := i
-			executors[i] = func(ctx context.Context) error {
-				resultChan <- taskID
-				return nil
-			}
-		}
-
-		ctx := context.Background()
-		err := NewParallelExecutor(5, executors...)(ctx)
-		assert.NoError(t, err) //nolint:testifylint // pre-existing issue from nektos/act
-
-		close(resultChan)
-
-		results := make(map[int]bool)
-		for result := range resultChan {
-			results[result] = true
-		}
-
-		assert.Len(t, results, 50, "All task IDs should be received")
-	})
-}

act/common/executor_test.go

@@ -9,9 +9,9 @@ import (
 	"errors"
 	"reflect"
 	"strings"
+	"sync"
 	"sync/atomic"
 	"testing"
-	"time"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -82,44 +82,45 @@ func TestNewConditionalExecutor(t *testing.T) {
 	assert.Equal(1, falseCount)
 }
 
-func TestNewParallelExecutor(t *testing.T) {
-	assert := assert.New(t)
+// concurrencyProbe returns an executor recording the peak number of concurrent copies. Copies
+// block until wantActive are in flight so the peak is exact without sleeping, and later copies
+// find the gate already open so the last one still finishes with no partner left.
+func concurrencyProbe(wantActive int32) (exec Executor, count, maxActive *atomic.Int32) {
+	var counted, active, peak atomic.Int32
+	var once sync.Once
+	reached := make(chan struct{})
 
-	ctx := context.Background()
-
-	var count, activeCount, maxCount atomic.Int32
-	emptyWorkflow := NewPipelineExecutor(func(ctx context.Context) error {
-		count.Add(1)
-
-		active := activeCount.Add(1)
+	return func(ctx context.Context) error {
+		counted.Add(1)
+		running := active.Add(1)
 		for {
-			m := maxCount.Load()
-			if active <= m || maxCount.CompareAndSwap(m, active) {
+			seen := peak.Load()
+			if running <= seen || peak.CompareAndSwap(seen, running) {
 				break
 			}
 		}
-		time.Sleep(2 * time.Second)
-		activeCount.Add(-1)
-
+		if running >= wantActive {
+			once.Do(func() { close(reached) })
+		}
+		<-reached
+		active.Add(-1)
 		return nil
-	})
+	}, &counted, &peak
+}
 
-	err := NewParallelExecutor(2, emptyWorkflow, emptyWorkflow, emptyWorkflow)(ctx)
+func TestNewParallelExecutor(t *testing.T) {
+	ctx := context.Background()
 
-	assert.Equal(int32(3), count.Load(), "should run all 3 executors")
-	assert.Equal(int32(2), maxCount.Load(), "should run at most 2 executors in parallel")
-	assert.NoError(err) //nolint:testifylint // pre-existing issue from nektos/act
+	exec, count, maxActive := concurrencyProbe(2)
+	require.NoError(t, NewParallelExecutor(2, exec, exec, exec)(ctx))
+	assert.Equal(t, int32(3), count.Load(), "should run all 3 executors")
+	assert.Equal(t, int32(2), maxActive.Load(), "should run at most 2 executors in parallel")
 
-	// Reset to test running the executor with 0 parallelism
-	count.Store(0)
-	activeCount.Store(0)
-	maxCount.Store(0)
-
-	errSingle := NewParallelExecutor(0, emptyWorkflow, emptyWorkflow, emptyWorkflow)(ctx)
-
-	assert.Equal(int32(3), count.Load(), "should run all 3 executors")
-	assert.Equal(int32(1), maxCount.Load(), "should run at most 1 executors in parallel")
-	assert.NoError(errSingle)
+	// parallelism below 1 falls back to a single worker
+	exec, count, maxActive = concurrencyProbe(1)
+	require.NoError(t, NewParallelExecutor(0, exec, exec, exec)(ctx))
+	assert.Equal(t, int32(3), count.Load(), "should run all 3 executors")
+	assert.Equal(t, int32(1), maxActive.Load(), "should run at most 1 executor in parallel")
 }
 
 func TestNewParallelExecutorEmpty(t *testing.T) {
@@ -173,6 +174,23 @@ func TestNewParallelExecutorCanceled(t *testing.T) {
 	assert.Error(errExpected, err) //nolint:testifylint // pre-existing issue from nektos/act
 }
 
+func TestNewParallelExecutorRunsRemainingAfterFailure(t *testing.T) {
+	var successCount atomic.Int32
+	executors := make([]Executor, 5)
+	for i := range executors {
+		executors[i] = func(ctx context.Context) error {
+			if i == 2 {
+				return errors.New("fake error")
+			}
+			successCount.Add(1)
+			return nil
+		}
+	}
+
+	require.Error(t, NewParallelExecutor(2, executors...)(context.Background()))
+	assert.Equal(t, int32(4), successCount.Load(), "a failing executor must not stop the others")
+}
+
 func TestExecutorConditionalsAndFinally(t *testing.T) {
 	ctx := context.Background()
 	var calls []string

act/runner/helpers_test.go

@@ -5,11 +5,9 @@ package runner
 
 import (
 	"context"
-	"net"
 	"os/exec"
 	"runtime"
 	"testing"
-	"time"
 
 	"gitea.com/gitea/runner/act/container"
 
@@ -42,18 +40,6 @@ func requireDocker(t *testing.T) {
 	}
 }
 
-// requireNetwork skips the test unless github.com is reachable. A few tests exercise behaviour
-// that inherently needs the network (force-pulling an image, resolving a remote short-sha ref);
-// gating lets the rest of the suite run offline without these failing.
-func requireNetwork(t *testing.T) {
-	t.Helper()
-	conn, err := net.DialTimeout("tcp", "github.com:443", 3*time.Second)
-	if err != nil {
-		t.Skipf("skipping: network unavailable: %v", err)
-	}
-	_ = conn.Close()
-}
-
 // requireHostTools skips the test unless every named executable is on PATH. Used by the
 // self-hosted (host environment) suite, which runs steps directly on the host.
 func requireHostTools(t *testing.T, tools ...string) {

act/runner/job_executor_test.go

@@ -33,6 +33,7 @@ import (
 )
 
 func TestJobExecutor(t *testing.T) {
+	t.Parallel()
 	// Dryrun only checks syntax/planning; all cases resolve locally, so this runs offline.
 	tables := []TestJobFileInfo{
 		{workdir, "uses-and-run-in-one-step", "push", "Invalid run/uses syntax for job:test step:Test", platforms, secrets},
@@ -46,6 +47,7 @@ func TestJobExecutor(t *testing.T) {
 	ctx := common.WithDryrun(context.Background(), true)
 	for _, table := range tables {
 		t.Run(table.workflowPath, func(t *testing.T) {
+			t.Parallel()
 			table.runTest(ctx, t, &Config{})
 		})
 	}

act/runner/runner_max_parallel_test.go

@@ -1,109 +0,0 @@
-// Copyright 2026 The Gitea Authors. All rights reserved.
-// SPDX-License-Identifier: MIT
-
-package runner
-
-import (
-	"sync"
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/assert"
-)
-
-// TestMaxParallelConfig tests that MaxParallel config is properly set
-func TestMaxParallelConfig(t *testing.T) {
-	t.Run("MaxParallel set to 2", func(t *testing.T) {
-		config := &Config{
-			Workdir:     "testdata",
-			MaxParallel: 2,
-		}
-
-		runner, err := New(config)
-		assert.NoError(t, err) //nolint:testifylint // pre-existing issue from nektos/act
-		assert.NotNil(t, runner)
-
-		// Verify config is properly stored
-		runnerImpl, ok := runner.(*runnerImpl)
-		assert.True(t, ok)
-		assert.Equal(t, 2, runnerImpl.config.MaxParallel)
-	})
-
-	t.Run("MaxParallel set to 0 (no limit)", func(t *testing.T) {
-		config := &Config{
-			Workdir:     "testdata",
-			MaxParallel: 0,
-		}
-
-		runner, err := New(config)
-		assert.NoError(t, err) //nolint:testifylint // pre-existing issue from nektos/act
-		assert.NotNil(t, runner)
-
-		runnerImpl, ok := runner.(*runnerImpl)
-		assert.True(t, ok)
-		assert.Equal(t, 0, runnerImpl.config.MaxParallel)
-	})
-
-	t.Run("MaxParallel not set (defaults to 0)", func(t *testing.T) {
-		config := &Config{
-			Workdir: "testdata",
-		}
-
-		runner, err := New(config)
-		assert.NoError(t, err) //nolint:testifylint // pre-existing issue from nektos/act
-		assert.NotNil(t, runner)
-
-		runnerImpl, ok := runner.(*runnerImpl)
-		assert.True(t, ok)
-		assert.Equal(t, 0, runnerImpl.config.MaxParallel)
-	})
-}
-
-// TestMaxParallelConcurrencyTracking tests that max-parallel actually limits concurrent execution
-func TestMaxParallelConcurrencyTracking(t *testing.T) {
-	// This is a unit test for the parallel executor logic
-	// We test that when MaxParallel is set, it limits the number of workers
-
-	var mu sync.Mutex
-	var maxConcurrent int
-	var currentConcurrent int
-
-	// Create a function that tracks concurrent execution
-	trackingFunc := func() {
-		mu.Lock()
-		currentConcurrent++
-		if currentConcurrent > maxConcurrent {
-			maxConcurrent = currentConcurrent
-		}
-		mu.Unlock()
-
-		// Simulate work
-		time.Sleep(50 * time.Millisecond)
-
-		mu.Lock()
-		currentConcurrent--
-		mu.Unlock()
-	}
-
-	// Run multiple tasks with limited parallelism
-	maxConcurrent = 0
-	currentConcurrent = 0
-
-	// This simulates what NewParallelExecutor does with a semaphore
-	var wg sync.WaitGroup
-	semaphore := make(chan struct{}, 2) // Limit to 2 concurrent
-
-	for range 6 {
-		wg.Go(func() {
-			semaphore <- struct{}{}        // Acquire
-			defer func() { <-semaphore }() // Release
-			trackingFunc()
-		})
-	}
-
-	wg.Wait()
-
-	// With a semaphore of 2, max concurrent should be <= 2
-	assert.LessOrEqual(t, maxConcurrent, 2, "Maximum concurrent executions should not exceed limit")
-	assert.GreaterOrEqual(t, maxConcurrent, 1, "Should have at least 1 concurrent execution")
-}

act/runner/runner_test.go

@@ -13,6 +13,7 @@ import (
 	"path"
 	"path/filepath"
 	"runtime"
+	"slices"
 	"strings"
 	"testing"
 	"time"
@@ -163,6 +164,12 @@ func TestGraphEvent(t *testing.T) {
 	assert.Empty(t, plan.Stages)
 }
 
+// these two build the same action Dockerfiles into one image tag, so they cannot overlap
+var sharedImageWorkflows = []string{"local-action-dockerfile", "local-action-via-composite-dockerfile"}
+
+// bounds concurrent plans: each job holds a network, and the daemon's address pool is finite
+var planSlots = make(chan struct{}, 4)
+
 type TestJobFileInfo struct {
 	workdir      string
 	workflowPath string
@@ -182,12 +189,19 @@ func (j *TestJobFileInfo) runTest(ctx context.Context, t *testing.T, cfg *Config
 
 	fullWorkflowPath := filepath.Join(workdir, j.workflowPath)
 	runnerConfig := &Config{
-		Workdir:               workdir,
-		BindWorkdir:           false,
-		EventName:             j.eventName,
-		EventPath:             cfg.EventPath,
-		Platforms:             j.platforms,
-		ReuseContainers:       false,
+		Workdir:     workdir,
+		BindWorkdir: false,
+		EventName:   j.eventName,
+		EventPath:   cfg.EventPath,
+		Platforms:   j.platforms,
+		// fixtures reuse workflow and job names, so parallel tests would collide without this
+		ContainerNamePrefix: strings.ReplaceAll(t.Name(), "/", "-"),
+		ReuseContainers:     false,
+		// as the shipped runner does, else a fixture asserting a job failure keeps its
+		// container, and its network, on the daemon forever
+		AutoRemove: true,
+		// 0 would run jobs runtime.NumCPU()-wide, making the network peak machine-dependent
+		MaxParallel:           2,
 		ForceRebuild:          true,
 		Env:                   cfg.Env,
 		Secrets:               cfg.Secrets,
@@ -210,7 +224,11 @@ func (j *TestJobFileInfo) runTest(ctx context.Context, t *testing.T, cfg *Config
 	plan, err := planner.PlanEvent(j.eventName)
 	assert.True(t, (err == nil) != (plan == nil), "PlanEvent should return either a plan or an error") //nolint:testifylint // pre-existing issue from nektos/act
 	if err == nil && plan != nil {
-		err = runner.NewPlanExecutor(plan)(ctx)
+		err = func() error {
+			planSlots <- struct{}{}
+			defer func() { <-planSlots }()
+			return runner.NewPlanExecutor(plan)(ctx)
+		}()
 		if j.errorMessage == "" {
 			assert.NoError(t, err, fullWorkflowPath) //nolint:testifylint // pre-existing issue from nektos/act
 		} else {
@@ -227,6 +245,7 @@ type TestConfig struct {
 
 func TestRunEvent(t *testing.T) {
 	requireDocker(t)
+	t.Parallel()
 
 	ctx := context.Background()
 
@@ -315,6 +334,9 @@ func TestRunEvent(t *testing.T) {
 				// host /proc bind mounts are Linux-Docker-only
 				requireLinuxDocker(t)
 			}
+			if !slices.Contains(sharedImageWorkflows, table.workflowPath) {
+				t.Parallel()
+			}
 
 			config := &Config{
 				Secrets: table.secrets,
@@ -445,6 +467,7 @@ func TestRunEventHostEnvironment(t *testing.T) {
 }
 
 func TestDryrunEvent(t *testing.T) {
+	t.Parallel()
 	// Dryrun plans without containers or network (shells and local actions only).
 	ctx := common.WithDryrun(context.Background(), true)
 
@@ -464,6 +487,7 @@ func TestDryrunEvent(t *testing.T) {
 
 	for _, table := range tables {
 		t.Run(table.workflowPath, func(t *testing.T) {
+			t.Parallel()
 			table.runTest(ctx, t, &Config{})
 		})
 	}
@@ -474,33 +498,11 @@ func TestDryrunEvent(t *testing.T) {
 // workflow's outputs via `needs`).
 func TestReusableWorkflowCaller(t *testing.T) {
 	requireDocker(t)
+	t.Parallel()
 	table := TestJobFileInfo{workdir, "uses-workflow", "push", "", platforms, map[string]string{"secret": "keep_it_private"}}
 	table.runTest(context.Background(), t, &Config{Secrets: table.secrets})
 }
 
-func TestDockerActionForcePullForceRebuild(t *testing.T) {
-	requireDocker(t)
-	requireNetwork(t) // force-pulls a docker action image
-
-	ctx := context.Background()
-
-	config := &Config{
-		ForcePull:    true,
-		ForceRebuild: true,
-	}
-
-	tables := []TestJobFileInfo{
-		{workdir, "local-action-dockerfile", "push", "", platforms, secrets},
-		{workdir, "local-action-via-composite-dockerfile", "push", "", platforms, secrets},
-	}
-
-	for _, table := range tables {
-		t.Run(table.workflowPath, func(t *testing.T) {
-			table.runTest(ctx, t, config)
-		})
-	}
-}
-
 type maskJobLoggerFactory struct {
 	Output bytes.Buffer
 }
@@ -513,6 +515,7 @@ func (f *maskJobLoggerFactory) WithJobLogger() *log.Logger {
 }
 
 func TestMaskValues(t *testing.T) {
+	t.Parallel()
 	assertNoSecret := func(text, secret string) { //nolint:unparam // pre-existing issue from nektos/act
 		found := strings.Contains(text, "composite secret")
 		if found {
@@ -543,6 +546,7 @@ func TestMaskValues(t *testing.T) {
 
 func TestRunEventSecrets(t *testing.T) {
 	requireDocker(t)
+	t.Parallel()
 	workflowPath := "secrets"
 
 	tjfi := TestJobFileInfo{
@@ -598,6 +602,7 @@ func TestRunWithService(t *testing.T) {
 }
 
 func TestRunActionInputs(t *testing.T) {
+	t.Parallel()
 	requireDocker(t)
 	workflowPath := "input-from-cli"
 
@@ -617,6 +622,7 @@ func TestRunActionInputs(t *testing.T) {
 }
 
 func TestRunEventPullRequest(t *testing.T) {
+	t.Parallel()
 	requireDocker(t)
 
 	workflowPath := "pull-request"
@@ -633,6 +639,7 @@ func TestRunEventPullRequest(t *testing.T) {
 }
 
 func TestRunMatrixWithUserDefinedInclusions(t *testing.T) {
+	t.Parallel()
 	requireDocker(t)
 	workflowPath := "matrix-with-user-inclusions"