test: never write the real user state dirs from tests

internal/agent/agent_test.go

@@ -20,8 +20,14 @@ func TestNewSubagentOrchestratorWithGemmaThinking(t *testing.T) {
 	cfg := client.Config{BaseURL: "http://localhost:8080"}
 	c := client.NewClient(cfg)
 
-	// Create a mock parent session
-	mockHistoryPath := "/tmp/mock-session.json"
+	// Create a mock parent session. Spawning a subagent reserves the parent's
+	// next child sequence via NextChildID → UpdateSubagentSeq, which persists
+	// the parent's .meta.json sidecar into the sessions dir — redirect the
+	// sessions dir to a temp dir so nothing lands in the real user dir.
+	tmp := t.TempDir()
+	setSessionDirForTest(t, tmp)
+
+	mockHistoryPath := filepath.Join(tmp, "mock-session.json")
 	mockHistory := []client.ChatMessage{}
 	mockSession := session.New(c, mockHistoryPath, mockHistory, "mock system prompt", true)
 	parent := orchestrator.NewBaseOrchestrator("parent", mockSession, nil, 100)
@@ -101,8 +107,14 @@ func TestNewSubagentOrchestratorGemmaThinkingWithCWD(t *testing.T) {
 	cfg := client.Config{BaseURL: "http://localhost:8080"}
 	c := client.NewClient(cfg)
 
+	// Spawning a subagent persists the parent's .meta.json sidecar (see
+	// TestNewSubagentOrchestratorWithGemmaThinking) — redirect the sessions
+	// dir to a temp dir.
+	tmp := t.TempDir()
+	setSessionDirForTest(t, tmp)
+
 	// Create a mock parent session
-	mockHistoryPath := "/tmp/mock-session.json"
+	mockHistoryPath := filepath.Join(tmp, "mock-session.json")
 	mockHistory := []client.ChatMessage{}
 	mockSession := session.New(c, mockHistoryPath, mockHistory, "mock system prompt", true)
 	parent := orchestrator.NewBaseOrchestrator("parent", mockSession, nil, 100)
@@ -160,9 +172,15 @@ func min(a, b int) int {
 
 // TestNewSubagentOrchestratorID verifies that the created subagent ID contains its agent type
 func TestNewSubagentOrchestratorID(t *testing.T) {
+	// Spawning a subagent persists the parent's .meta.json sidecar (see
+	// TestNewSubagentOrchestratorWithGemmaThinking) — redirect the sessions
+	// dir to a temp dir.
+	tmp := t.TempDir()
+	setSessionDirForTest(t, tmp)
+
 	cfg := client.Config{BaseURL: "http://localhost:8080"}
 	c := client.NewClient(cfg)
-	mockSession := session.New(c, "/tmp/mock-session.json", []client.ChatMessage{}, "mock system prompt", true)
+	mockSession := session.New(c, filepath.Join(tmp, "mock-session.json"), []client.ChatMessage{}, "mock system prompt", true)
 	parent := orchestrator.NewBaseOrchestrator("parent", mockSession, nil, 100)
 
 	child, err := NewSubagentOrchestrator(
@@ -187,14 +205,21 @@ func TestNewSubagentOrchestratorID(t *testing.T) {
 		t.Errorf("Expected child ID to contain 'coder', got %s", child.ID())
 	}
 }
+
 // TestNewSubagentOrchestrator_ConcurrentSpawn is the FR2 regression test:
 // concurrent spawns against a shared parent must never mint duplicate child IDs.
 func TestNewSubagentOrchestrator_ConcurrentSpawn(t *testing.T) {
+	// Each spawn persists the parent's .meta.json sidecar (see
+	// TestNewSubagentOrchestratorWithGemmaThinking) — 16 concurrent spawns
+	// would hammer the real sessions dir without the redirect.
+	tmp := t.TempDir()
+	setSessionDirForTest(t, tmp)
+
 	cfg := client.Config{BaseURL: "http://localhost:8080"}
 	c := client.NewClient(cfg)
 
 	// Create a shared mock parent session and orchestrator
-	mockSession := session.New(c, "/tmp/mock-session.json", []client.ChatMessage{}, "mock system prompt", true)
+	mockSession := session.New(c, filepath.Join(tmp, "mock-session.json"), []client.ChatMessage{}, "mock system prompt", true)
 	parent := orchestrator.NewBaseOrchestrator("parent", mockSession, nil, 10)
 
 	const numSpawn = 16
@@ -539,10 +564,16 @@ func TestNewSubagentOrchestrator_ResumedParentUsesNextHistoryPath(t *testing.T)
 // TestSubagentRegistryHasNoTodoTools verifies that a spawned subagent NEVER
 // receives todo tools in its registry, even when enabledTools includes them.
 func TestSubagentRegistryHasNoTodoTools(t *testing.T) {
+	// Spawning a subagent persists the parent's .meta.json sidecar (see
+	// TestNewSubagentOrchestratorWithGemmaThinking) — redirect the sessions
+	// dir to a temp dir.
+	tmp := t.TempDir()
+	setSessionDirForTest(t, tmp)
+
 	cfg := client.Config{BaseURL: "http://localhost:8080"}
 	c := client.NewClient(cfg)
 
-	mockSession := session.New(c, "/tmp/mock-session.json", []client.ChatMessage{}, "mock system prompt", true)
+	mockSession := session.New(c, filepath.Join(tmp, "mock-session.json"), []client.ChatMessage{}, "mock system prompt", true)
 	parent := orchestrator.NewBaseOrchestrator("parent", mockSession, nil, 100)
 
 	enabledTools := map[string]bool{
@@ -590,4 +621,3 @@ func TestSubagentRegistryHasNoTodoTools(t *testing.T) {
 		t.Fatalf("expected subagent registry to contain read_file")
 	}
 }
-

internal/executor/executor_test.go

@@ -123,8 +123,25 @@ func TestStreamAccumulator_NameUpdate(t *testing.T) {
 	}
 }
 
+// isolateSessionDir points the session layer's global SessionDir at a fresh
+// temp directory for the duration of the test. SaveSessionMeta derives the
+// .meta.json sidecar path from SessionDir() — the shared sessions directory —
+// and NOT from the history file's directory (production requires this: the
+// --continue lister scans the sessions dir for sidecars), so every test that
+// persists history (any Add*Message → saveAndNotify → UpdateSessionMetadata)
+// would otherwise write e.g. history.meta.json into the REAL
+// ~/.local/share/late/sessions. Redirecting SessionDir keeps all test writes
+// inside t.TempDir().
+func isolateSessionDir(t *testing.T) {
+	t.Helper()
+	oldDir := session.SessionDir
+	session.SessionDir = func() (string, error) { return t.TempDir(), nil }
+	t.Cleanup(func() { session.SessionDir = oldDir })
+}
+
 // TestExecuteToolCalls_NotFound verifies that missing tools produce an error message
 func TestExecuteToolCalls_NotFound(t *testing.T) {
+	isolateSessionDir(t)
 	c := client.NewClient(client.Config{BaseURL: "http://localhost:0"})
 	histPath := filepath.Join(t.TempDir(), "history.json")
 	sess := session.New(c, histPath, nil, "", false)
@@ -149,6 +166,7 @@ func TestExecuteToolCalls_NotFound(t *testing.T) {
 
 // TestExecuteToolCalls_Denied verifies denied confirmation produces cancel message
 func TestExecuteToolCalls_Denied(t *testing.T) {
+	isolateSessionDir(t)
 	c := client.NewClient(client.Config{BaseURL: "http://localhost:0"})
 	histPath := filepath.Join(t.TempDir(), "history.json")
 	sess := session.New(c, histPath, nil, "", true)
@@ -182,6 +200,7 @@ func TestExecuteToolCalls_Denied(t *testing.T) {
 // TestExecuteToolCalls_NoMiddlewareFailsClosed verifies shell commands cannot
 // run when confirmation middleware is missing.
 func TestExecuteToolCalls_NoMiddlewareFailsClosed(t *testing.T) {
+	isolateSessionDir(t)
 	c := client.NewClient(client.Config{BaseURL: "http://localhost:0"})
 	histPath := filepath.Join(t.TempDir(), "history.json")
 	sess := session.New(c, histPath, nil, "", true)
@@ -395,4 +414,3 @@ func TestRunLoop_PreCancelledContextDoesNotInvokeStartTurn(t *testing.T) {
 		t.Fatal("onStartTurn was invoked despite cancelled context")
 	}
 }
-

internal/orchestrator/base_test.go

@@ -2,14 +2,14 @@ package orchestrator
 
 import (
 	"context"
-	"fmt"
 	"encoding/json"
+	"fmt"
 	"late/internal/client"
 	"late/internal/common"
 	"late/internal/session"
+	"late/internal/tool"
 	"net/http"
 	"net/http/httptest"
-	"late/internal/tool"
 	"os"
 	"path/filepath"
 	"sync"
@@ -277,14 +277,22 @@ func TestNextChildIDPersistsSequenceForResume(t *testing.T) {
 }
 
 func TestBaseOrchestrator_Execute_EmptyTextDoesNotAddMessage(t *testing.T) {
+	// Execute's run loop commits via AddAssistantMessageWithTools →
+	// saveAndNotify → UpdateSessionMetadata, which writes the .meta.json
+	// sidecar into the global sessions dir. Redirect it so nothing leaves
+	// the temp dir.
+	tmpDir := t.TempDir()
+	originalSessionDir := session.SessionDir
+	session.SessionDir = func() (string, error) { return tmpDir, nil }
+	t.Cleanup(func() { session.SessionDir = originalSessionDir })
+
 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "text/event-stream")
 		w.WriteHeader(http.StatusOK)
 		_, _ = w.Write([]byte("data: [DONE]\n\n"))
 	}))
 	defer ts.Close()
 
-	tmpDir := t.TempDir()
 	historyPath := filepath.Join(tmpDir, "session.json")
 	initial := []client.ChatMessage{
 		{Role: "user", Content: client.TextContent("initial goal")},
@@ -370,6 +378,15 @@ func TestBaseOrchestrator_CancelClearsQueuedMessages(t *testing.T) {
 }
 
 func TestBaseOrchestrator_CancelDuringRunDoesNotCommitQueuedMessages(t *testing.T) {
+	// The "turn 1" submit runs a full turn: AddUserMessage + the run-loop's
+	// AddAssistantMessageWithTools both persist via saveAndNotify →
+	// UpdateSessionMetadata, writing the .meta.json sidecar into the global
+	// sessions dir. Redirect it so nothing leaves the temp dir.
+	tmpDir := t.TempDir()
+	originalSessionDir := session.SessionDir
+	session.SessionDir = func() (string, error) { return tmpDir, nil }
+	t.Cleanup(func() { session.SessionDir = originalSessionDir })
+
 	// Setup a server that holds the connection until cancelled
 	holdCh := make(chan struct{})
 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
@@ -381,7 +398,6 @@ func TestBaseOrchestrator_CancelDuringRunDoesNotCommitQueuedMessages(t *testing.
 	defer ts.Close()
 	defer close(holdCh)
 
-	tmpDir := t.TempDir()
 	historyPath := filepath.Join(tmpDir, "session.json")
 	c := client.NewClient(client.Config{BaseURL: ts.URL})
 	sess := session.New(c, historyPath, nil, "", false)

internal/plugin/example_plugin_test.go

@@ -237,6 +237,11 @@ func TestExamplePlugin_AllAPIs(t *testing.T) {
 // TestExamplePlugin_CLICommands tests installing via 'late plugin link',
 // listing, enabling, disabling, and removing.
 func TestExamplePlugin_CLICommands(t *testing.T) {
+	// Sandbox the user config dir: link/enable/disable/remove all record
+	// state in the global plugin state file (plugins.json), which must be
+	// a throwaway here.
+	sandboxUserConfig(t)
+
 	wd, err := os.Getwd()
 	if err != nil {
 		t.Fatal(err)

internal/plugin/project_test.go

@@ -209,6 +209,10 @@ func TestDiscover_IgnoresNodeModulesAndCache(t *testing.T) {
 // ---------------------------------------------------------------------------
 
 func TestInstallFromLocal_Project(t *testing.T) {
+	// Sandbox the user config dir: this flow records state in the global
+	// plugin state file (plugins.json), which must be a throwaway here.
+	sandboxUserConfig(t)
+
 	globalDir := t.TempDir()
 	projectDir := t.TempDir()
 	sourceDir := t.TempDir()
@@ -246,6 +250,10 @@ func TestInstallFromLocal_Project(t *testing.T) {
 }
 
 func TestInstallFromLocal_Global(t *testing.T) {
+	// Sandbox the user config dir: this flow records state in the global
+	// plugin state file (plugins.json), which must be a throwaway here.
+	sandboxUserConfig(t)
+
 	globalDir := t.TempDir()
 	projectDir := t.TempDir()
 	sourceDir := t.TempDir()
@@ -270,6 +278,10 @@ func TestInstallFromLocal_Global(t *testing.T) {
 // ---------------------------------------------------------------------------
 
 func TestLink_Project(t *testing.T) {
+	// Sandbox the user config dir: Link records state in the global plugin
+	// state file (plugins.json), which must be a throwaway here.
+	sandboxUserConfig(t)
+
 	globalDir := t.TempDir()
 	projectDir := t.TempDir()
 	sourceDir := t.TempDir()
@@ -290,6 +302,10 @@ func TestLink_Project(t *testing.T) {
 }
 
 func TestLink_Global(t *testing.T) {
+	// Sandbox the user config dir: Link records state in the global plugin
+	// state file (plugins.json), which must be a throwaway here.
+	sandboxUserConfig(t)
+
 	globalDir := t.TempDir()
 	projectDir := t.TempDir()
 	sourceDir := t.TempDir()
@@ -314,6 +330,11 @@ func TestLink_Global(t *testing.T) {
 // ---------------------------------------------------------------------------
 
 func TestRemovePlugin_Project(t *testing.T) {
+	// Sandbox the user config dir: installing/removing a local plugin
+	// records and clears state in the global plugin state file
+	// (plugins.json), which must be a throwaway here.
+	sandboxUserConfig(t)
+
 	globalDir := t.TempDir()
 	projectDir := t.TempDir()
 	sourceDir := t.TempDir()
@@ -350,6 +371,11 @@ func TestRemovePlugin_Project(t *testing.T) {
 }
 
 func TestRemovePlugin_Global(t *testing.T) {
+	// Sandbox the user config dir: installing/removing a local plugin
+	// records and clears state in the global plugin state file
+	// (plugins.json), which must be a throwaway here.
+	sandboxUserConfig(t)
+
 	globalDir := t.TempDir()
 	projectDir := t.TempDir()
 	sourceDir := t.TempDir()
@@ -571,6 +597,11 @@ func writeScopedPluginLike(t *testing.T, dir, scopedName string) string {
 }
 
 func TestRemovePlugin_ScopedLink_CleansEmptyScopeParent(t *testing.T) {
+	// Sandbox the user config dir: installing/removing a local plugin
+	// records and clears state in the global plugin state file
+	// (plugins.json), which must be a throwaway here.
+	sandboxUserConfig(t)
+
 	globalDir := t.TempDir()
 	sourceDir := t.TempDir()
 	writeScopedPluginLike(t, sourceDir, "@late/scoped-plugin")
@@ -598,6 +629,11 @@ func TestRemovePlugin_ScopedLink_CleansEmptyScopeParent(t *testing.T) {
 }
 
 func TestRemovePlugin_ScopedLink_KeepsNonEmptyScopeParent(t *testing.T) {
+	// Sandbox the user config dir: installing/removing a local plugin
+	// records and clears state in the global plugin state file
+	// (plugins.json), which must be a throwaway here.
+	sandboxUserConfig(t)
+
 	globalDir := t.TempDir()
 	srcA := t.TempDir()
 	srcB := t.TempDir()
@@ -636,6 +672,11 @@ func TestRemovePlugin_ScopedLink_KeepsNonEmptyScopeParent(t *testing.T) {
 // installs — the `dir` parameter flows through pm.TargetDir(project), but
 // without an explicit test the project's branch is never asserted.
 func TestRemovePlugin_Project_ScopedLink_CleansEmptyScopeParent(t *testing.T) {
+	// Sandbox the user config dir: installing/removing a local plugin
+	// records and clears state in the global plugin state file
+	// (plugins.json), which must be a throwaway here.
+	sandboxUserConfig(t)
+
 	globalDir := t.TempDir()
 	projectDir := t.TempDir()
 	sourceDir := t.TempDir()