test: add LatencyReader unit tests

Author: devgianlu

audio/latency_test.go

@@ -0,0 +1,102 @@
+//go:build test_unit
+
+package audio_test
+
+import (
+	"bytes"
+	"io"
+	"testing"
+	"time"
+
+	"github.com/devgianlu/go-librespot/audio"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestLatencyReader(t *testing.T) {
+	testData := "Hello, World! This is test data for latency measurement."
+	reader := &slowTestReader{
+		data:  []byte(testData),
+		delay: 50 * time.Millisecond,
+	}
+
+	var measuredLatency time.Duration
+	latencyReader := &audio.LatencyReader{
+		Reader: reader,
+		Callback: func(latency time.Duration) {
+			measuredLatency = latency
+		},
+	}
+
+	// Read all data
+	buf := make([]byte, len(testData))
+	n, err := latencyReader.Read(buf)
+	require.NoError(t, err)
+	assert.Equal(t, len(testData), n)
+	assert.Equal(t, testData, string(buf))
+
+	// Ensure EOF is reached
+	_, err = latencyReader.Read(buf)
+	assert.ErrorIs(t, err, io.EOF)
+
+	// Verify latency was measured
+	assert.Greater(t, measuredLatency, time.Duration(0))
+}
+
+func TestLatencyReaderMultipleReads(t *testing.T) {
+	testData := "Hello, World! This is test data for multiple reads."
+	reader := &slowTestReader{
+		data:  []byte(testData),
+		delay: 50 * time.Millisecond,
+	}
+
+	var latencies []time.Duration
+	latencyReader := &audio.LatencyReader{
+		Reader: reader,
+		Callback: func(latency time.Duration) {
+			latencies = append(latencies, latency)
+		},
+	}
+
+	// Read data in chunks
+	buf := make([]byte, 10)
+	var result bytes.Buffer
+
+	for {
+		n, err := latencyReader.Read(buf)
+		if err == io.EOF {
+			break
+		}
+		require.NoError(t, err)
+		result.Write(buf[:n])
+	}
+
+	assert.Equal(t, testData, result.String())
+	assert.Greater(t, len(latencies), 0)
+
+	// All latencies should be positive
+	for _, latency := range latencies {
+		assert.Greater(t, latency, time.Duration(0))
+	}
+}
+
+// Helper for testing slow reads
+type slowTestReader struct {
+	data  []byte
+	pos   int
+	delay time.Duration
+}
+
+func (r *slowTestReader) Read(p []byte) (n int, err error) {
+	if r.delay > 0 {
+		time.Sleep(r.delay)
+	}
+
+	if r.pos >= len(r.data) {
+		return 0, io.EOF
+	}
+
+	n = copy(p, r.data[r.pos:])
+	r.pos += n
+	return n, nil
+}