Add session discovery and template support

internal/app/session_cli_test.go

@@ -0,0 +1,86 @@
+package app
+
+import (
+	"bytes"
+	"context"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestPlanUsesDiscoveredSessionTemplateWithSessionID(t *testing.T) {
+	workspaceRoot := t.TempDir()
+	pipelinePath, sessionPath := writeValidConfigFiles(t, workspaceRoot)
+
+	sessionTemplate := `session_id: "{{ session_id }}"
+campaign: sample-campaign
+inputs:
+  audio_dir: ./audio
+  speakers_file: ./speakers.yml
+  autocorrect_file: ./autocorrect.yml
+  glossary_file: ./glossary.yml
+`
+	if err := os.WriteFile(sessionPath, []byte(sessionTemplate), 0o644); err != nil {
+		t.Fatalf("write session template: %v", err)
+	}
+
+	cwd := filepath.Dir(sessionPath)
+	originalWD, err := os.Getwd()
+	if err != nil {
+		t.Fatalf("Getwd(): %v", err)
+	}
+	if err := os.Chdir(cwd); err != nil {
+		t.Fatalf("Chdir(%q): %v", cwd, err)
+	}
+	t.Cleanup(func() { _ = os.Chdir(originalWD) })
+
+	var out bytes.Buffer
+	if err := Plan(context.Background(), []string{"--config", pipelinePath, "--session-id", "2026-04-04"}, &out); err != nil {
+		t.Fatalf("Plan() error = %v", err)
+	}
+	if !strings.Contains(out.String(), "narratio plan: workdir prepared") {
+		t.Fatalf("output = %q, want plan output", out.String())
+	}
+}
+
+func TestPlanFailsWhenSessionIDMismatchesConcreteSession(t *testing.T) {
+	workspaceRoot := t.TempDir()
+	pipelinePath, sessionPath := writeValidConfigFiles(t, workspaceRoot)
+
+	var out bytes.Buffer
+	err := Plan(context.Background(), []string{"--config", pipelinePath, "--session", sessionPath, "--session-id", "2026-04-04"}, &out)
+	if err == nil {
+		t.Fatal("expected error, got nil")
+	}
+	if !strings.Contains(err.Error(), "session_id mismatch") {
+		t.Fatalf("error = %q, want mismatch context", err.Error())
+	}
+}
+
+func TestRunStageAcceptsSessionIDFlagAndParsesStageName(t *testing.T) {
+	workspaceRoot := t.TempDir()
+	pipelinePath, sessionPath := writeValidConfigFiles(t, workspaceRoot)
+
+	var out bytes.Buffer
+	err := RunStage(context.Background(), []string{"--config", pipelinePath, "--session", sessionPath, "--session-id", "2026-05-03", "prepare"}, &out)
+	if err != nil {
+		t.Fatalf("RunStage() error = %v", err)
+	}
+	if !strings.Contains(out.String(), "stage=prepare") {
+		t.Fatalf("output = %q, want stage output", out.String())
+	}
+}
+
+func TestResolveSessionConfigPathErrorIncludesSearchedPaths(t *testing.T) {
+	_, err := resolveSessionConfigPathWithCandidates("", []string{"./session.yml", "/usr/local/etc/narratio/session.yml", "/etc/narratio/session.yml"})
+	if err == nil {
+		t.Fatal("expected error, got nil")
+	}
+	if !strings.Contains(err.Error(), "searched") {
+		t.Fatalf("error = %q, want searched paths", err.Error())
+	}
+	if !strings.Contains(err.Error(), "pass --session") {
+		t.Fatalf("error = %q, want explicit-session guidance", err.Error())
+	}
+}