From cf30414c2a0696cc75c615f4da66ea85d0522c42 Mon Sep 17 00:00:00 2001
From: Paul Buetow <paul@buetow.org>
Date: Wed, 29 Apr 2026 19:43:05 +0300
Subject: feat: implement filesystem scanner

---
 internal/thumb/thumb_test.go | 80 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 internal/thumb/thumb_test.go

(limited to 'internal/thumb/thumb_test.go')

diff --git a/internal/thumb/thumb_test.go b/internal/thumb/thumb_test.go
new file mode 100644
index 0000000..2cd6124
--- /dev/null
+++ b/internal/thumb/thumb_test.go
@@ -0,0 +1,80 @@
+package thumb
+
+import (
+	"context"
+	"errors"
+	"os/exec"
+	"strings"
+	"testing"
+)
+
+func TestFFmpegGenerator_Generate(t *testing.T) {
+	ctx := context.Background()
+	called := false
+
+	fakeExecer := func(_ context.Context, name string, arg ...string) *exec.Cmd {
+		called = true
+		if name != "ffmpeg" {
+			t.Errorf("expected ffmpeg, got %s", name)
+		}
+		// Verify some expected flags exist.
+		args := strings.Join(arg, " ")
+		if !strings.Contains(args, "-ss") {
+			t.Error("missing -ss flag")
+		}
+		if !strings.Contains(args, "-i") {
+			t.Error("missing -i flag")
+		}
+		if !strings.Contains(args, "-frames:v 1") {
+			t.Error("missing -frames:v 1 flag")
+		}
+		if !strings.Contains(args, "-y") {
+			t.Error("missing -y flag")
+		}
+		// Return a command that does nothing successfully.
+		return exec.Command("true")
+	}
+
+	g := &FFmpegGenerator{execer: fakeExecer}
+	if err := g.Generate(ctx, "input.mp4", "output.jpg", 120.0); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if !called {
+		t.Fatal("expected fake execer to be called")
+	}
+
+	// Duration zero or negative should still call execer with valid offset.
+	called = false
+	if err := g.Generate(ctx, "input.mp4", "output.jpg", 0); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if !called {
+		t.Fatal("expected fake execer to be called for zero duration")
+	}
+}
+
+func TestFFmpegGenerator_Generate_Error(t *testing.T) {
+	ctx := context.Background()
+	fakeExecer := func(_ context.Context, name string, arg ...string) *exec.Cmd {
+		return exec.Command("false")
+	}
+	g := &FFmpegGenerator{execer: fakeExecer}
+	if err := g.Generate(ctx, "input.mp4", "output.jpg", 10.0); err == nil {
+		t.Fatal("expected error from failing ffmpeg command")
+	}
+}
+
+func TestMockGenerator(t *testing.T) {
+	ctx := context.Background()
+	m := &MockGenerator{}
+	if err := m.Generate(ctx, "in", "out", 0); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	m.GenerateFunc = func(context.Context, string, string, float64) error {
+		return errors.New("fail")
+	}
+	if err := m.Generate(ctx, "in", "out", 0); err == nil {
+		t.Fatal("expected error from mock generator")
+	}
+}
-- 
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