Fix dump-conf to always return configuration

Previously in case of missing ffmpeg, ffprobe or VMAF model files
auto-detection mechanism would end execution and there was no chance to
mend situation even with -conf flag and working configuration file.

Now auto-detecting mechanism for default configuration will list "not
found" and configuration verification will catch the issue. Upside being
that one can get a rough configuration on systems with unconventional
tool locations, which can be used as a basis for configuration file.

config.go

@@ -95,25 +95,25 @@ func (c *Config) OverrideFrom(src Config) {
 //
 // For some configuration options a default value will be specified, for others an
 // auto-detection mechanism will populate option values.
-func loadDefaultConfig() (Config, error) {
+func loadDefaultConfig() Config {
 	var cfg Config
 
 	// For default configuration attempt to locate ffmpeg binary.
 	ffmpeg, err := tools.FfmpegPath()
 	if err != nil {
-		return cfg, fmt.Errorf("DefaultConfig: %w", err)
+		ffmpeg = "not found"
 	}
 
 	// For default configuration attempt to locate ffprobe binary.
 	ffprobe, err := tools.FfprobePath()
 	if err != nil {
-		return cfg, fmt.Errorf("DefaultConfig: %w", err)
+		ffprobe = "not found"
 	}
 
 	// For default configuration attempt to locate VMAF model file.
 	libvmafModel, err := tools.FindLibvmafModel()
 	if err != nil {
-		return cfg, fmt.Errorf("DefaultConfig: %w", err)
+		libvmafModel = "not found"
 	}
 
 	cfg = Config{
@@ -124,7 +124,7 @@ func loadDefaultConfig() (Config, error) {
 		ReportFileName:     NewConfigVal(defaultReportFile),
 	}
 
-	return cfg, nil
+	return cfg
 }
 
 // loadConfigFromFile will load configuration from file.
@@ -144,10 +144,7 @@ func loadConfigFromFile(f string) (cfg Config, err error) {
 // function to use for config loading. Configuration file is optional e.g. can be "".
 func LoadConfig(configFile string) (cfg Config, err error) {
 	// Initialize default configuration.
-	cfg, err = loadDefaultConfig()
-	if err != nil {
-		return cfg, err
-	}
+	cfg = loadDefaultConfig()
 
 	// Load configuration from file and override default configuration options.
 	if configFile != "" {

config_test.go

@@ -17,18 +17,16 @@ import (
 )
 
 func Test_loadDefaultConfig(t *testing.T) {
-	c, err := loadDefaultConfig()
-	assert.NoError(t, err, "Should create DefaultConfig without errors")
-
+	c := loadDefaultConfig()
 	assert.NoError(t, c.Verify(), "DefaultConfig should be valid")
 }
 
 func Test_loadDefaultConfig_Negative(t *testing.T) {
 	// Messing up PATH should result in failure detecting ffmpeg and ffprobe which
 	// should result in error from calling DefaultConfig().
 	t.Setenv("PATH", "")
-	_, err := loadDefaultConfig()
-	assert.ErrorContains(t, err, "DefaultConfig: ")
+	c := loadDefaultConfig()
+	assert.Error(t, c.Verify())
 }
 
 func Test_loadConfigFile(t *testing.T) {
@@ -153,7 +151,6 @@ func Test_Config_OverrideFrom(t *testing.T) {
 }
 
 func Test_DumpConfApp_Run(t *testing.T) {
-	commandOutput := &bytes.Buffer{}
 	// This is one option we try to make sure is in dumped config file.
 	want := `"report_file_name": "test_report.json"`
 
@@ -166,10 +163,28 @@ func Test_DumpConfApp_Run(t *testing.T) {
 	cmd := CreateDumpConfCommand()
 
 	// Redirect output to buffer
+	commandOutput := &bytes.Buffer{}
 	cmd.out = commandOutput
 
 	err := cmd.Run([]string{"-conf", confFile})
 	assert.NoError(t, err, "Unexpected error running encode")
 	// Check that config dump contains options we specified in config file.
 	assert.Contains(t, commandOutput.String(), want)
 }
+
+func Test_DumpConfApp_Run_WithNotFound(t *testing.T) {
+	// This will make ffmpeg and ffprobe auto-detect to fail.
+	t.Setenv("PATH", "")
+
+	// Run command will generate encoding artifacts and analysis artifacts.
+	cmd := CreateDumpConfCommand()
+
+	// Redirect output to buffer
+	commandOutput := &bytes.Buffer{}
+	cmd.out = commandOutput
+
+	err := cmd.Run([]string{})
+	assert.Contains(t, commandOutput.String(), `"ffmpeg_path": "not found"`)
+	assert.Contains(t, commandOutput.String(), `"ffprobe_path": "not found"`)
+	assert.ErrorContains(t, err, "configuration validation")
+}