How to use Fallback method of got Package

...154type buildFunc func(t *testing.T, tc testCase) Catalog155func initBuilder(t *testing.T, tc testCase) Catalog {156	options := []Option{}157	if tc.fallback != "" {158		options = append(options, Fallback(language.MustParse(tc.fallback)))159	}160	cat := NewBuilder(options...)161	for _, e := range tc.cat {162		tag := language.MustParse(e.tag)163		switch msg := e.msg.(type) {164		case string:165			cat.SetString(tag, e.key, msg)166		case Message:167			cat.Set(tag, e.key, msg)168		case []Message:169			cat.Set(tag, e.key, msg...)170		}171	}172	setMacros(cat)173	return cat174}175type dictionary map[string]string176func (d dictionary) Lookup(key string) (data string, ok bool) {177	data, ok = d[key]178	return data, ok179}180func initCatalog(t *testing.T, tc testCase) Catalog {181	m := map[string]Dictionary{}182	for _, e := range tc.cat {183		m[e.tag] = dictionary{}184	}185	for _, e := range tc.cat {186		var msg Message187		switch x := e.msg.(type) {188		case string:189			msg = String(x)190		case Message:191			msg = x192		case []Message:193			msg = firstInSequence(x)194		}195		data, _ := catmsg.Compile(language.MustParse(e.tag), nil, msg)196		m[e.tag].(dictionary)[e.key] = data197	}198	options := []Option{}199	if tc.fallback != "" {200		options = append(options, Fallback(language.MustParse(tc.fallback)))201	}202	c, err := NewFromMap(m, options...)203	if err != nil {204		t.Fatal(err)205	}206	// TODO: implement macros for fixed catalogs.207	b := NewBuilder()208	setMacros(b)209	c.(*catalog).macros.index = b.macros.index210	return c211}212func TestMatcher(t *testing.T) {213	test := func(t *testing.T, init buildFunc) {214		for _, tc := range testCases {...

1package envget_test2import (3	"os"4	"reflect"5	"testing"6	"time"7	"github.com/johejo/go-envget"8)9func TestGetString(t *testing.T) {10	tests := []struct {11		name, key, value, fallback, want string12	}{13		{name: "get value", key: "TEST_KEY", value: "TEST_VALUE", fallback: "TEST_FALLBACK", want: "TEST_VALUE"},14		{name: "get fallback", key: "TEST_KEY", value: "", fallback: "TEST_FALLBACK", want: "TEST_FALLBACK"},15	}16	for _, tt := range tests {17		t.Run(tt.name, func(t *testing.T) {18			setEnv(t, tt.key, tt.value)19			got := envget.GetString(tt.key, tt.fallback)20			if got != tt.want {21				t.Errorf("want=%v, but got %v", tt.want, got)22			}23		})24	}25}26func TestGetInt(t *testing.T) {27	tests := []struct {28		name, key, value string29		fallback, want   int30	}{31		{name: "get 0", key: "TEST_KEY", value: "0", fallback: 99, want: 0},32		{name: "get 1", key: "TEST_KEY", value: "1", fallback: 99, want: 1},33		{name: "get fallback", key: "TEST_KEY", value: "", fallback: 99, want: 99},34		{name: "invalid value", key: "TEST_KEY", value: "xyz", fallback: 99, want: 99},35	}36	for _, tt := range tests {37		t.Run(tt.name, func(t *testing.T) {38			setEnv(t, tt.key, tt.value)39			got := envget.GetInt(tt.key, tt.fallback)40			if got != tt.want {41				t.Errorf("want=%v, but got %v", tt.want, got)42			}43		})44	}45}46func TestGetBool(t *testing.T) {47	tests := []struct {48		name, key, value string49		fallback, want   bool50	}{51		{name: "get 0", key: "TEST_KEY", value: "0", fallback: true, want: false},52		{name: "get 1", key: "TEST_KEY", value: "1", fallback: false, want: true},53		{name: "get true", key: "TEST_KEY", value: "true", fallback: false, want: true},54		{name: "get True", key: "TEST_KEY", value: "True", fallback: false, want: true},55		{name: "get TRUE", key: "TEST_KEY", value: "TRUE", fallback: false, want: true},56		{name: "get fallback", key: "TEST_KEY", value: "", fallback: true, want: true},57		{name: "invalid value", key: "TEST_KEY", value: "xyz", fallback: true, want: true},58	}59	for _, tt := range tests {60		t.Run(tt.name, func(t *testing.T) {61			setEnv(t, tt.key, tt.value)62			got := envget.GetBool(tt.key, tt.fallback)63			if got != tt.want {64				t.Errorf("want=%v, but got %v", tt.want, got)65			}66		})67	}68}69func TestGetDuration(t *testing.T) {70	tests := []struct {71		name, key, value string72		fallback, want   time.Duration73	}{74		{name: "get 0", key: "TEST_KEY", value: "0ns", fallback: 99 * time.Second, want: 0 * time.Nanosecond},75		{name: "get 1", key: "TEST_KEY", value: "1ms", fallback: 99 * time.Second, want: 1 * time.Millisecond},76		{name: "get fallback", key: "TEST_KEY", value: "", fallback: 99 * time.Second, want: 99 * time.Second},77		{name: "invalid format", key: "TEST_KEY", value: "xyx", fallback: 99 * time.Second, want: 99 * time.Second},78	}79	for _, tt := range tests {80		t.Run(tt.name, func(t *testing.T) {81			setEnv(t, tt.key, tt.value)82			got := envget.GetDuration(tt.key, tt.fallback)83			if got != tt.want {84				t.Errorf("want=%v, but got %v", tt.want, got)85			}86		})87	}88}89func TestGetStringSlice(t *testing.T) {90	tests := []struct {91		name, key, value string92		fallback, want   []string93	}{94		{name: "get one value", key: "TEST_KEY", value: "A", fallback: []string{"F"}, want: []string{"A"}},95		{name: "get one value", key: "TEST_KEY", value: "A,", fallback: []string{"F"}, want: []string{"A"}},96		{name: "get one value", key: "TEST_KEY", value: ",A,", fallback: []string{"F"}, want: []string{"A"}},97		{name: "get one value", key: "TEST_KEY", value: ",A", fallback: []string{"F"}, want: []string{"A"}},98		{name: "get multi value", key: "TEST_KEY", value: "A,B", fallback: []string{"F"}, want: []string{"A", "B"}},99		{name: "get multi value", key: "TEST_KEY", value: "A, B", fallback: []string{"F"}, want: []string{"A", "B"}},100		{name: "get multi value", key: "TEST_KEY", value: ",A, B", fallback: []string{"F"}, want: []string{"A", "B"}},101		{name: "get multi value", key: "TEST_KEY", value: "A,B,", fallback: []string{"F"}, want: []string{"A", "B"}},102		{name: "get fallback value", key: "TEST_KEY", value: "", fallback: []string{"F"}, want: []string{"F"}},103	}104	for _, tt := range tests {105		t.Run(tt.name, func(t *testing.T) {106			setEnv(t, tt.key, tt.value)107			got := envget.GetStringSlice(tt.key, tt.fallback)108			if !reflect.DeepEqual(tt.want, got) {109				t.Errorf("want=%v, but got %v", tt.want, got)110			}111		})112	}113}114func setEnv(t *testing.T, key, value string) {115	t.Helper()116	if err := os.Setenv(key, value); err != nil {117		t.Fatal(err)118	}119	t.Cleanup(func() {120		if err := os.Unsetenv(key); err != nil {121			t.Fatal(err)122		}123	})124}...

1import (2func main() {3	var i interface{} = "hello"4	s := i.(string)5	fmt.Println(s)6	s, ok := i.(string)7	fmt.Println(s, ok)8	f, ok := i.(float64)9	fmt.Println(f, ok)10	fmt.Println(f)11}12panic: interface conversion: interface {} is string, not float6413main.main()14import (15func main() {16	var i interface{} = "hello"17	s := i.(string)18	fmt.Println(s)19	s, ok := i.(string)20	fmt.Println(s, ok)21	f, ok := i.(float64)22	fmt.Println(f, ok)23	fmt.Println(f, ok)24}25import (26func main() {27	var i interface{} = "hello"28	s := i.(string)29	fmt.Println(s)30	s, ok := i.(string)31	fmt.Println(s, ok)32	f, ok := i.(float64)33	fmt.Println(f, ok)34	fmt.Println(f)35}36panic: interface conversion: interface {} is string, not float6437main.main()38import (39func main() {40	var i interface{} = "hello"41	s := i.(string)42	fmt.Println(s)43	s, ok := i.(string)44	fmt.Println(s, ok)45	f, ok := i.(float64)46	fmt.Println(f, ok)47	fmt.Println(f, ok)48}

1func main() {2    got.Fallback()3}4func main() {5    got.Fallback()6}7func main() {8    got.Fallback()9}10func main() {11    got.Fallback()12}13func main() {14    got.Fallback()15}16func main() {17    got.Fallback()18}19func main() {20    got.Fallback()21}22func main() {23    got.Fallback()24}25func main() {26    got.Fallback()27}28func main() {29    got.Fallback()30}31func main() {32    got.Fallback()33}34func main() {35    got.Fallback()36}37func main() {38    got.Fallback()39}40func main() {41    got.Fallback()42}43func main() {44    got.Fallback()45}46func main() {47    got.Fallback()48}49func main() {50    got.Fallback()51}52func main() {53    got.Fallback()54}

1import "fmt"2func main() {3    fmt.Println("Hello, world.")4}5import "fmt"6func main() {7    fmt.Println("Hello, world.")8}9import "fmt"10func main() {11    fmt.Println("Hello, world.")12}13import "fmt"14func main() {15    fmt.Println("Hello, world.")16}17import "fmt"18func main() {19    fmt.Println("Hello, world.")20}21import "fmt"22func main() {23    fmt.Println("Hello, world.")24}25import "fmt"26func main() {27    fmt.Println("Hello, world.")28}29import "fmt"30func main() {31    fmt.Println("Hello, world.")32}33import "fmt"34func main() {35    fmt.Println("Hello, world.")36}37import "fmt"38func main() {39    fmt.Println("Hello, world.")40}41import "fmt"42func main() {43    fmt.Println("Hello, world.")44}45import "fmt"46func main() {47    fmt.Println("Hello, world.")48}49import "fmt"50func main() {51    fmt.Println("Hello, world.")52}53import

1import (2func main() {3	app := cli.NewApp()4	app.Commands = []cli.Command{5		{6			Subcommands: []cli.Command{7				{8					Action: func(c *cli.Context) error {9						fmt.Println("Hello friend!")10					},11				},12			},13		},14	}15	app.Run(os.Args)16}

1func main() {2    fmt.Println("Hello, playground")3    got.Fallback()4}5func main() {6    fmt.Println("Hello, playground")7    got.Fallback()8}9func main() {10    fmt.Println("Hello, playground")11    got.Fallback()12}13func main() {14    fmt.Println("Hello, playground")15    got.Fallback()16}17func main() {18    fmt.Println("Hello, playground")19    got.Fallback()20}21func main() {22    fmt.Println("Hello, playground")23    got.Fallback()24}25func main() {26    fmt.Println("Hello, playground")27    got.Fallback()28}29func main() {30    fmt.Println("Hello, playground")31    got.Fallback()32}33func main() {34    fmt.Println("Hello, playground")35    got.Fallback()36}37func main() {38    fmt.Println("Hello, playground")39    got.Fallback()40}41func main() {42    fmt.Println("Hello, playground")43    got.Fallback()44}45func main() {46    fmt.Println("Hello, playground")47    got.Fallback()48}49func main() {50    fmt.Println("Hello, playground")51    got.Fallback()52}53func main() {54    fmt.Println("Hello, playground")55    got.Fallback()56}

1import "fmt"2func main() {3    var i interface{} = 7.94    s := i.(int)5    fmt.Println(s)6}7panic: interface conversion: interface {} is float64, not int8main.main()9import "fmt"10func main() {11    var i interface{} = 7.912    s, ok := i.(int)13    fmt.Println(s, ok)14}15import "fmt"16func main() {17    var i interface{} = 7.918    s, ok := i.(int)19    if ok {20        fmt.Println(s)21    } else {22        fmt.Println("Conversion failed")23    }24}

1import (2func main() {3    fmt.Println(got.Fallback("Hello", "World"))4}5import (6func main() {7    fmt.Println(got.Fallback("Hello", ""))8}9import (10func main() {11    fmt.Println(got.Fallback("", "World"))12}13import (14func main() {15    fmt.Println(got.Fallback("", ""))16}17import (18func main() {19    fmt.Println(got.Fallback("Hello", "World"))20}

1import (2func main() {3	fmt.Println("Hello World")4}5import (6func main() {7	fmt.Println("Hello World")8}9import (10func main() {11	fmt.Println("Hello World")12}13import (14func main() {15	fmt.Println("Hello World")16}17import (18func main() {19	fmt.Println("Hello World")20}21import (22func main() {23	fmt.Println("Hello World")24}25import (26func main() {27	fmt.Println("Hello World")28}29import (30func main() {31	fmt.Println("Hello World")32}33import (34func main() {35	fmt.Println("Hello World")36}

1import (2func main() {3	wd, err := got.Getwd()4	if err != nil {5		fmt.Println(err)6	}7	fmt.Println(wd)8}9import (10func main() {11	wd, err := got.Getwd()12	if err != nil {13		fmt.Println(err)14	}15	fmt.Println(wd)16}17import (18func main() {19	wd, err := got.Getwd()20	if err != nil {21		fmt.Println(err)22	}23	fmt.Println(wd)24}25import (26func main() {27	wd, err := got.Getwd()28	if err != nil {29		fmt.Println(err)30	}31	fmt.Println(wd)32}33import (34func main() {35	wd, err := got.Getwd()36	if err != nil {37		fmt.Println(err)38	}39	fmt.Println(wd)40}41import (42func main() {