test(02-02): add failing tests for PPID chain walk + workspace resolution

- TestReadPPID, TestReadPPIDMissing
- TestResolveWorkspace, TestResolveWorkspaceNotFound, TestResolveWorkspaceMaxDepth
- TestBuildTerminalWorkspaceMapUnit
- Add go.i3wm.org/i3/v4 dependency

workspace_test.go

@@ -0,0 +1,169 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"testing"
+
+	i3 "go.i3wm.org/i3/v4"
+)
+
+// --- Helpers ---
+
+func writeFakeStatus(t *testing.T, procDir string, pid, ppid int) {
+	t.Helper()
+	pidDir := filepath.Join(procDir, fmt.Sprintf("%d", pid))
+	if err := os.MkdirAll(pidDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	content := fmt.Sprintf("Name:\tprocess\nPPid:\t%d\nUid:\t1000\n", ppid)
+	if err := os.WriteFile(filepath.Join(pidDir, "status"), []byte(content), 0o644); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// --- Mock types ---
+
+type mockI3TreeProvider struct {
+	tree i3.Tree
+	err  error
+}
+
+func (m *mockI3TreeProvider) GetTree() (i3.Tree, error) {
+	return m.tree, m.err
+}
+
+type mockX11PIDResolver struct {
+	pids map[int64]int // windowID -> PID
+}
+
+func (m *mockX11PIDResolver) GetPID(windowID int64) (int, error) {
+	pid, ok := m.pids[windowID]
+	if !ok {
+		return 0, fmt.Errorf("no PID for window %d", windowID)
+	}
+	return pid, nil
+}
+
+// --- ReadPPID tests ---
+
+func TestReadPPID(t *testing.T) {
+	procDir := t.TempDir()
+	writeFakeStatus(t, procDir, 100, 50)
+
+	ppid, err := ReadPPID(procDir, 100)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if ppid != 50 {
+		t.Errorf("ReadPPID = %d, want 50", ppid)
+	}
+}
+
+func TestReadPPIDMissing(t *testing.T) {
+	procDir := t.TempDir()
+
+	_, err := ReadPPID(procDir, 999)
+	if err == nil {
+		t.Fatal("expected error for missing PID, got nil")
+	}
+}
+
+// --- ResolveWorkspace tests ---
+
+func TestResolveWorkspace(t *testing.T) {
+	procDir := t.TempDir()
+	// Chain: 100 -> 50 -> 10
+	writeFakeStatus(t, procDir, 100, 50)
+	writeFakeStatus(t, procDir, 50, 10)
+	writeFakeStatus(t, procDir, 10, 1)
+
+	terminalMap := map[int]string{10: "workspace 3"}
+
+	ws := ResolveWorkspace(procDir, 100, terminalMap)
+	if ws != "workspace 3" {
+		t.Errorf("ResolveWorkspace = %q, want %q", ws, "workspace 3")
+	}
+}
+
+func TestResolveWorkspaceNotFound(t *testing.T) {
+	procDir := t.TempDir()
+	writeFakeStatus(t, procDir, 100, 50)
+	writeFakeStatus(t, procDir, 50, 1)
+	writeFakeStatus(t, procDir, 1, 0)
+
+	terminalMap := map[int]string{999: "workspace 5"}
+
+	ws := ResolveWorkspace(procDir, 100, terminalMap)
+	if ws != "" {
+		t.Errorf("ResolveWorkspace = %q, want empty", ws)
+	}
+}
+
+func TestResolveWorkspaceMaxDepth(t *testing.T) {
+	procDir := t.TempDir()
+	// Chain of 25 PIDs: 100 -> 99 -> 98 -> ... -> 76
+	for pid := 100; pid > 75; pid-- {
+		writeFakeStatus(t, procDir, pid, pid-1)
+	}
+	// PID 75 is in the terminal map but depth > 20
+	terminalMap := map[int]string{75: "workspace 1"}
+
+	ws := ResolveWorkspace(procDir, 100, terminalMap)
+	if ws != "" {
+		t.Errorf("ResolveWorkspace should return empty after max depth, got %q", ws)
+	}
+}
+
+// --- BuildTerminalWorkspaceMap tests ---
+
+func TestBuildTerminalWorkspaceMapUnit(t *testing.T) {
+	// Mock i3 tree with 2 workspaces, each containing a window
+	tree := i3.Tree{
+		Root: &i3.Node{
+			Type: i3.Root,
+			Nodes: []*i3.Node{
+				{
+					Type: i3.OutputNode,
+					Name: "eDP-1",
+					Nodes: []*i3.Node{
+						{
+							Type: i3.WorkspaceNode,
+							Name: "1",
+							Nodes: []*i3.Node{
+								{Type: i3.Con, Window: 12345},
+							},
+						},
+						{
+							Type: i3.WorkspaceNode,
+							Name: "3",
+							Nodes: []*i3.Node{
+								{Type: i3.Con, Window: 67890},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+
+	x11 := &mockX11PIDResolver{
+		pids: map[int64]int{
+			12345: 1000,
+			67890: 2000,
+		},
+	}
+
+	result, err := BuildTerminalWorkspaceMap(&mockI3TreeProvider{tree: tree}, x11)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if result[1000] != "1" {
+		t.Errorf("PID 1000 workspace = %q, want %q", result[1000], "1")
+	}
+	if result[2000] != "3" {
+		t.Errorf("PID 2000 workspace = %q, want %q", result[2000], "3")
+	}
+}