Probably should name the custom packages specially

1 files changed, 76 insertions, 0 deletions

diff --git a/internal/flatex/decompress_test.go b/internal/flatex/decompress_test.go
new file mode 100644
index 00000000..afb84292
--- /dev/null
+++ b/internal/flatex/decompress_test.go
@@ -0,0 +1,76 @@
+package flatex
+
+import (
+	"bytes"
+	stdflate "compress/flate"
+	"testing"
+)
+
+func compressDeflate(t *testing.T, payload, dict []byte) []byte {
+	t.Helper()
+	var buf bytes.Buffer
+	var (
+		w   *stdflate.Writer
+		err error
+	)
+	if dict != nil {
+		w, err = stdflate.NewWriterDict(&buf, stdflate.DefaultCompression, dict)
+	} else {
+		w, err = stdflate.NewWriter(&buf, stdflate.DefaultCompression)
+	}
+	if err != nil {
+		t.Fatalf("NewWriter: %v", err)
+	}
+	if _, err := w.Write(payload); err != nil {
+		t.Fatalf("Write: %v", err)
+	}
+	if err := w.Close(); err != nil {
+		t.Fatalf("Close: %v", err)
+	}
+	return buf.Bytes()
+}
+
+func TestDecompress(t *testing.T) {
+	payload := bytes.Repeat([]byte("golang"), 32)
+	compressed := compressDeflate(t, payload, nil)
+
+	out, _, err := Decompress(compressed)
+	if err != nil {
+		t.Fatalf("Decompress: %v", err)
+	}
+	defer out.Release()
+
+	if !bytes.Equal(out.Bytes(), payload) {
+		t.Fatalf("unexpected payload: got %q", out.Bytes())
+	}
+}
+
+func TestDecompressDict(t *testing.T) {
+	dict := []byte("furgit dictionary payload")
+	payload := append([]byte(nil), dict...)
+	payload = append(payload, []byte(" -- and some more data repeated -- and some more data repeated")...)
+
+	compressed := compressDeflate(t, payload, dict)
+
+	out, _, err := DecompressDict(compressed, dict)
+	if err != nil {
+		t.Fatalf("DecompressDict: %v", err)
+	}
+	defer out.Release()
+
+	if !bytes.Equal(out.Bytes(), payload) {
+		t.Fatalf("unexpected payload: got %q", out.Bytes())
+	}
+}
+
+func TestDecompressDictMissing(t *testing.T) {
+	dict := []byte("shared prefix to enforce dictionary usage")
+	payload := append([]byte(nil), dict...)
+	payload = append(payload, []byte(" trailing data to force reference")...)
+
+	compressed := compressDeflate(t, payload, dict)
+
+	if _, _, err := Decompress(compressed); err == nil {
+		t.Fatalf("expected error when dictionary missing")
+	}
+}