111 lines
3.9 KiB
Go
111 lines
3.9 KiB
Go
package transcode
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import (
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"encoding/binary"
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"errors"
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"math"
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"testing"
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)
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// TestWAVHeaderFields 逐字段断言 44 字节头（design/25 §3.1：不重采样、8 kHz、
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// 单声道、PCM16）。
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func TestWAVHeaderFields(t *testing.T) {
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const samples = 160
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dataBytes := samples * wavPCMBytesPerSample
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hdr, err := wavHeader(dataBytes, amrSampleRate, amrChannels)
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if err != nil {
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t.Fatalf("wavHeader: %v", err)
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}
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if len(hdr) != wavHeaderBytes {
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t.Fatalf("header length = %d, want %d", len(hdr), wavHeaderBytes)
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}
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if string(hdr[wavOffRiffID:wavOffChunkSize]) != wavRiffID ||
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string(hdr[wavOffWaveID:wavOffFmtID]) != wavWaveID ||
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string(hdr[wavOffFmtID:wavOffFmtSize]) != wavFmtID ||
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string(hdr[wavOffDataID:wavOffDataSize]) != wavDataID {
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t.Fatalf("chunk ids wrong: %q %q %q %q",
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hdr[wavOffRiffID:wavOffChunkSize], hdr[wavOffWaveID:wavOffFmtID],
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hdr[wavOffFmtID:wavOffFmtSize], hdr[wavOffDataID:wavOffDataSize])
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}
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checks := []struct {
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name string
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got uint32
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want uint32
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}{
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{"RIFF size", binary.LittleEndian.Uint32(hdr[wavOffChunkSize:]), uint32(riffChunkSizeBase + dataBytes)},
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{"fmt size", binary.LittleEndian.Uint32(hdr[wavOffFmtSize:]), wavFmtChunkBytes},
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{"sample rate", binary.LittleEndian.Uint32(hdr[wavOffSampleRate:]), uint32(amrSampleRate)},
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{"byte rate", binary.LittleEndian.Uint32(hdr[wavOffByteRate:]), uint32(amrSampleRate * wavPCMBytesPerSample)},
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{"data size", binary.LittleEndian.Uint32(hdr[wavOffDataSize:]), uint32(dataBytes)},
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}
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for _, c := range checks {
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if c.got != c.want {
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t.Errorf("%s = %d, want %d", c.name, c.got, c.want)
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}
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}
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if got := binary.LittleEndian.Uint16(hdr[wavOffAudioFormat:]); got != wavFormatPCM {
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t.Errorf("audio format = %d, want %d (PCM)", got, wavFormatPCM)
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}
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if got := binary.LittleEndian.Uint16(hdr[wavOffChannels:]); got != amrChannels {
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t.Errorf("channels = %d, want %d", got, amrChannels)
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}
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if got := binary.LittleEndian.Uint16(hdr[wavOffBlockAlign:]); got != wavPCMBytesPerSample {
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t.Errorf("block align = %d, want %d", got, wavPCMBytesPerSample)
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}
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if got := binary.LittleEndian.Uint16(hdr[wavOffBitsPerSamp:]); got != wavBitsPerSample {
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t.Errorf("bits per sample = %d, want %d", got, wavBitsPerSample)
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}
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}
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// TestEncodePCM16WAVRoundTrip 断言样本 → WAV → 样本往返无损（小端正确）。
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func TestEncodePCM16WAVRoundTrip(t *testing.T) {
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samples := []int16{0, 1, -1, math.MaxInt16, math.MinInt16, 1234, -4321}
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wav, err := encodePCM16WAV(samples, amrSampleRate, amrChannels)
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if err != nil {
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t.Fatalf("encodePCM16WAV: %v", err)
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}
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got := wavDataSamples(t, wav)
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if len(got) != len(samples) {
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t.Fatalf("round trip samples = %d, want %d", len(got), len(samples))
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}
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for i := range samples {
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if got[i] != samples[i] {
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t.Fatalf("sample %d = %d, want %d", i, got[i], samples[i])
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}
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}
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}
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// TestWAVHeaderRejectsImpossibleDeclarations 断言不可能的头参数被拒（不写出
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// 一个长度撒谎的头）。
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func TestWAVHeaderRejectsImpossibleDeclarations(t *testing.T) {
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cases := []struct {
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name string
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dataBytes, rate, chans int
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}{
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{"zero rate", 2, 0, 1},
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{"negative rate", 2, -1, 1},
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{"zero channels", 2, amrSampleRate, 0},
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{"negative data", -1, amrSampleRate, 1},
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{"data beyond RIFF limit", int(wavMaxDataBytes) + 1, amrSampleRate, 1},
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}
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for _, tc := range cases {
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t.Run(tc.name, func(t *testing.T) {
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if _, err := wavHeader(tc.dataBytes, tc.rate, tc.chans); !errors.Is(err, ErrEncodeFailed) {
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t.Fatalf("err = %v, want ErrEncodeFailed", err)
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}
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})
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}
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}
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// TestWritePCM16LEIsLittleEndian 断言字节序：-2 = 0xFE 0xFF。
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func TestWritePCM16LEIsLittleEndian(t *testing.T) {
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dst := make([]byte, 2*wavPCMBytesPerSample)
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writePCM16LE(dst, []int16{-2, 258})
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if dst[0] != 0xFE || dst[1] != 0xFF {
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t.Fatalf("-2 写成 %#x %#x, want 0xfe 0xff", dst[0], dst[1])
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}
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if dst[2] != 0x02 || dst[3] != 0x01 {
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t.Fatalf("258 写成 %#x %#x, want 0x02 0x01", dst[2], dst[3])
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}
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}
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