Fix tests such that ffmpeg binary is not required

internal/.gitignore

@@ -0,0 +1,3 @@
+testhelper/ignoresigint/ignoresigint
+testhelper/sigint/sigint
+testhelper/ffmpeg/ffmpeg

internal/testhelper/ffmpeg/ffmpeg.go

@@ -0,0 +1,103 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"os/signal"
+	"time"
+)
+
+func main() {
+	header := `ffmpeg version 4.0.2 Copyright (c) 2000-2018 the FFmpeg developers
+  built with Apple LLVM version 9.1.0 (clang-902.0.39.2)
+  configuration: --prefix=/usr/local/Cellar/ffmpeg/4.0.2 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-gpl --enable-libmp3lame --enable-libx264 --enable-libx265 --enable-libxvid --enable-opencl --enable-videotoolbox --disable-lzma
+  libavutil      56. 14.100 / 56. 14.100
+  libavcodec     58. 18.100 / 58. 18.100
+  libavformat    58. 12.100 / 58. 12.100
+  libavdevice    58.  3.100 / 58.  3.100
+  libavfilter     7. 16.100 /  7. 16.100
+  libavresample   4.  0.  0 /  4.  0.  0
+  libswscale      5.  1.100 /  5.  1.100
+  libswresample   3.  1.100 /  3.  1.100
+  libpostproc    55.  1.100 / 55.  1.100`
+
+	prelude := `Input #0, lavfi, from 'testsrc=size=1280x720:rate=25':
+  Duration: N/A, start: 0.000000, bitrate: N/A
+    Stream #0:0: Video: rawvideo (RGB[24] / 0x18424752), rgb24, 1280x720 [SAR 1:1 DAR 16:9], 25 tbr, 25 tbn, 25 tbc
+Input #1, lavfi, from 'anullsrc=r=44100:cl=stereo':
+  Duration: N/A, start: 0.000000, bitrate: 705 kb/s
+    Stream #1:0: Audio: pcm_u8, 44100 Hz, stereo, u8, 705 kb/s
+	Stream #1:1(eng): Audio: aac (LC), 48000 Hz, stereo, fltp (default)
+Stream mapping:
+  Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
+  Stream #1:0 -> #0:1 (pcm_u8 (native) -> aac (native))
+Press [q] to stop, [?] for help
+[libx264 @ 0x7fa96a800600] using SAR=1/1
+[libx264 @ 0x7fa96a800600] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
+[libx264 @ 0x7fa96a800600] profile Constrained Baseline, level 3.1
+[libx264 @ 0x7fa96a800600] 264 - core 152 r2854 e9a5903 - H.264/MPEG-4 AVC codec - Copyleft 2003-2017 - http://www.videolan.org/x264.html - options: cabac=0 ref=1 deblock=0:0:0 analyse=0:0 me=dia subme=0 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=0 keyint=50 keyint_min=5 scenecut=0 intra_refresh=0 rc=crf mbtree=0 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=0
+[hls @ 0x7fa969803a00] Opening './data/testsrc5375.ts.tmp' for writing
+Output #0, hls, to './data/testsrc.m3u8':
+  Metadata:
+    encoder         : Lavf58.12.100
+    Stream #0:0: Video: h264 (libx264), yuv420p(progressive), 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 25 fps, 90k tbn, 25 tbc
+    Metadata:
+      encoder         : Lavc58.18.100 libx264
+    Side data:
+      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
+    Stream #0:1: Audio: aac (LC), 44100 Hz, stereo, fltp, 64 kb/s
+    Metadata:
+      encoder         : Lavc58.18.100 aac
+[hls @ 0x7fa969803a00] Opening './data/testsrc5376.ts.tmp' for writing=0.872x
+[hls @ 0x7fa969803a00] Opening './data/testsrc.m3u8.tmp' for writing
+[hls @ 0x7fa969803a00] Opening './data/testsrc.m3u8.tmp' for writing`
+
+	fmt.Fprintf(os.Stderr, "%s\n", header)
+
+	if len(os.Args) <= 1 {
+		os.Exit(2)
+	}
+
+	lastArg := os.Args[len(os.Args)-1]
+
+	if lastArg == "-version" {
+		os.Exit(0)
+	}
+
+	if len(lastArg) > 1 && lastArg[0] == '-' {
+		os.Exit(2)
+	}
+
+	fmt.Fprintf(os.Stderr, "%s\n", prelude)
+
+	ctx, cancel := context.WithCancel(context.Background())
+
+	go func(ctx context.Context) {
+		ticker := time.NewTicker(time.Second)
+		defer ticker.Stop()
+
+		frame := uint64(0)
+
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case <-ticker.C:
+				frame += 25
+				fmt.Fprintf(os.Stderr, "frame=%5d fps= 25 q=-1.0 Lsize=N/A time=00:00:02.32 bitrate=N/A speed=1.0x    \r", frame)
+			}
+		}
+	}(ctx)
+
+	// Wait for interrupt signal to gracefully shutdown the app
+	quit := make(chan os.Signal, 1)
+	signal.Notify(quit, os.Interrupt)
+	<-quit
+
+	cancel()
+
+	fmt.Fprintf(os.Stderr, "\nExiting normally, received signal 2.\n")
+
+	os.Exit(255)
+}

internal/testhelper/ignoresigint/ignoresigint.go

@@ -0,0 +1,17 @@
+package main
+
+import (
+	"os/signal"
+	"time"
+)
+
+func main() {
+	// Ignore all signals
+	signal.Ignore()
+
+	ticker := time.NewTicker(time.Second)
+	defer ticker.Stop()
+
+	for range ticker.C {
+	}
+}

internal/testhelper/sigint/sigint.go

@@ -0,0 +1,15 @@
+package main
+
+import (
+	"os"
+	"os/signal"
+)
+
+func main() {
+	// Wait for interrupt signal to gracefully shutdown the app
+	quit := make(chan os.Signal, 1)
+	signal.Notify(quit, os.Interrupt)
+	<-quit
+
+	os.Exit(255)
+}

internal/testhelper/testhelper.go

@@ -0,0 +1,21 @@
+package testhelper
+
+import (
+	"fmt"
+	"os/exec"
+	"path/filepath"
+)
+
+func BuildBinary(name, pathprefix string) (string, error) {
+	dir := filepath.Join(pathprefix, name)
+	aout := filepath.Join(dir, name)
+
+	fmt.Printf("aout: %s\n", aout)
+
+	err := exec.Command("go", "build", "-o", aout, dir).Run()
+	if err != nil {
+		return "", fmt.Errorf("build command: %w", err)
+	}
+
+	return aout, nil
+}