Add time formatting support

dump.go

@@ -11,6 +11,7 @@ import (
 	"sort"
 	"strconv"
 	"strings"
+	"time"
 )
 
 var (
@@ -40,6 +41,9 @@ type Options struct {
 	// when it's safe. This is useful for diffing two structures, where pointer variables would cause
 	// false changes. However, circular graphs are still detected and elided to avoid infinite output.
 	DisablePointerReplacement bool
+
+	// FormatTime, if true, will format [time.Time] values.
+	FormatTime bool
 }
 
 // Config is the default config used when calling Dump
@@ -59,6 +63,7 @@ type dumpState struct {
 	parentPointers    ptrmap
 	currentPointer    *ptrinfo
 	homePackageRegexp *regexp.Regexp
+	timeFormatter     func(t time.Time) string
 }
 
 func (s *dumpState) write(b []byte) {
@@ -129,6 +134,12 @@ func (s *dumpState) dumpSlice(v reflect.Value) {
 }
 
 func (s *dumpState) dumpStruct(v reflect.Value) {
+	val := v.Interface()
+	if t, ok := val.(time.Time); ok && s.timeFormatter != nil {
+		s.writeString(s.timeFormatter(t))
+		return
+	}
+
 	dumpPreamble := func() {
 		s.dumpType(v)
 		s.write([]byte("{"))
@@ -246,7 +257,6 @@ func (s *dumpState) dumpChan(v reflect.Value) {
 }
 
 func (s *dumpState) dumpCustom(v reflect.Value, buf *bytes.Buffer) {
-
 	// Dump the type
 	s.dumpType(v)
 
@@ -293,6 +303,8 @@ func (s *dumpState) dump(value interface{}) {
 	s.dumpVal(v)
 }
 
+var dumperType = reflect.TypeOf((*Dumper)(nil)).Elem()
+
 func (s *dumpState) descendIntoPossiblePointer(value reflect.Value, f func()) {
 	canonicalize := true
 	if isPointerValue(value) {
@@ -345,7 +357,6 @@ func (s *dumpState) dumpVal(value reflect.Value) {
 	}
 
 	// Handle custom dumpers
-	dumperType := reflect.TypeOf((*Dumper)(nil)).Elem()
 	if v.Type().Implements(dumperType) {
 		s.descendIntoPossiblePointer(v, func() {
 			// Run the custom dumper buffering the output
@@ -464,6 +475,16 @@ func newDumpState(value reflect.Value, options *Options, writer io.Writer) *dump
 		w:        writer,
 	}
 
+	if options.FormatTime {
+		result.timeFormatter = func(t time.Time) string {
+			t = t.In(time.UTC)
+			return fmt.Sprintf(
+				`time.Date(%d, %d, %d, %d, %d, %d, %d, time.UTC)`,
+				t.Year(), t.Month(), t.Day(), t.Hour(), t.Minute(), t.Second(), t.Nanosecond(),
+			)
+		}
+	}
+
 	if options.HomePackage != "" {
 		result.homePackageRegexp = regexp.MustCompile(fmt.Sprintf("\\b%s\\.", options.HomePackage))
 	}

dump_test.go

@@ -1,21 +1,22 @@
 package litter_test
 
 import (
+	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"reflect"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
 	"github.com/sanity-io/litter"
 )
 
-func Function(arg1 string, arg2 int) (string, error) {
+func Function(string, int) (string, error) {
 	return "", nil
 }
 
@@ -163,6 +164,7 @@ func TestSdump_config(t *testing.T) {
 		(func(v IntAlias) *IntAlias { return &v })(20),
 		litter.Dump,
 		func(s string, i int) (bool, error) { return false, nil },
+		time.Date(2018, 1, 1, 0, 0, 0, 0, time.UTC),
 	}
 
 	runTestWithCfg(t, "config_Compact", &litter.Options{
@@ -204,6 +206,9 @@ func TestSdump_config(t *testing.T) {
 			return false
 		},
 	}, data)
+	runTestWithCfg(t, "config_FormatTime", &litter.Options{
+		FormatTime: true,
+	}, data)
 
 	basic := &BasicStruct{1, 2}
 	runTestWithCfg(t, "config_DisablePointerReplacement_simpleReusedStruct", &litter.Options{
@@ -238,7 +243,7 @@ func TestSdump_maps(t *testing.T) {
 			2: "two",
 		},
 		map[int]*BlankStruct{
-			2: &BlankStruct{},
+			2: {},
 		},
 	})
 }
@@ -263,16 +268,19 @@ var standardCfg = litter.Options{}
 func runTestWithCfg(t *testing.T, name string, cfg *litter.Options, cases ...interface{}) {
 	t.Run(name, func(t *testing.T) {
 		fileName := fmt.Sprintf("testdata/%s.dump", name)
+
 		dump := cfg.Sdump(cases...)
-		reference, err := ioutil.ReadFile(fileName)
+
+		reference, err := os.ReadFile(fileName)
 		if os.IsNotExist(err) {
 			t.Logf("Note: Test data file %s does not exist, writing it; verify contents!", fileName)
-			err := ioutil.WriteFile(fileName, []byte(dump), 0644)
+			err := os.WriteFile(fileName, []byte(dump), 0644)
 			if err != nil {
 				t.Error(err)
 			}
 			return
 		}
+
 		assertEqualStringsWithDiff(t, string(reference), dump)
 	})
 }
@@ -286,17 +294,19 @@ func diffStrings(t *testing.T, expected, actual string) (*string, bool) {
 		return nil, true
 	}
 
-	dir, err := ioutil.TempDir("", "test")
+	dir, err := os.MkdirTemp("", "test")
 	require.NoError(t, err)
 	defer os.RemoveAll(dir)
 
-	require.NoError(t, ioutil.WriteFile(fmt.Sprintf("%s/expected", dir), []byte(expected), 0644))
-	require.NoError(t, ioutil.WriteFile(fmt.Sprintf("%s/actual", dir), []byte(actual), 0644))
+	require.NoError(t, os.WriteFile(fmt.Sprintf("%s/expected", dir), []byte(expected), 0644))
+	require.NoError(t, os.WriteFile(fmt.Sprintf("%s/actual", dir), []byte(actual), 0644))
 
 	out, err := exec.Command("diff", "--side-by-side",
 		fmt.Sprintf("%s/expected", dir),
 		fmt.Sprintf("%s/actual", dir)).Output()
-	if _, ok := err.(*exec.ExitError); !ok {
+
+	var exitErr *exec.ExitError
+	if !errors.As(err, &exitErr) {
 		require.NoError(t, err)
 	}
 

testdata/config_Compact.dump

@@ -1 +1 @@
-[]interface{}{litter_test.options{Compact:false,StripPackageNames:false,HidePrivateFields:true,HomePackage:"",Separator:" ",StrictGo:false},&litter_test.BasicStruct{Public:1,private:2},litter_test.Function,&20,&20,litter.Dump,func(string,int)(bool,error)}
+[]interface{}{litter_test.options{Compact:false,StripPackageNames:false,HidePrivateFields:true,HomePackage:"",Separator:" ",StrictGo:false},&litter_test.BasicStruct{Public:1,private:2},litter_test.Function,&20,&20,litter.Dump,func(string,int)(bool,error),time.Time{wall:0,ext:63650361600,loc:nil}}

testdata/config_DumpFunc.dump

@@ -16,4 +16,9 @@
   &20,
   litter.Dump,
   func(string, int) (bool, error),
+  time.Time{
+    wall: 0,
+    ext: 63650361600,
+    loc: nil,
+  },
 }

testdata/config_FieldFilter.dump

@@ -9,4 +9,5 @@
   &20,
   litter.Dump,
   func(string, int) (bool, error),
+  time.Time{},
 }

testdata/config_FormatTime.dump

@@ -0,0 +1,20 @@
+[]interface {}{
+  litter_test.options{
+    Compact: false,
+    StripPackageNames: false,
+    HidePrivateFields: true,
+    HomePackage: "",
+    Separator: " ",
+    StrictGo: false,
+  },
+  &litter_test.BasicStruct{
+    Public: 1,
+    private: 2,
+  },
+  litter_test.Function,
+  &20,
+  &20,
+  litter.Dump,
+  func(string, int) (bool, error),
+  time.Date(2018, 1, 1, 0, 0, 0, 0, time.UTC),
+}

testdata/config_HidePrivateFields.dump

@@ -15,4 +15,5 @@
   &20,
   litter.Dump,
   func(string, int) (bool, error),
+  time.Time{},
 }

testdata/config_HideZeroValues.dump

@@ -12,4 +12,8 @@
   &20,
   litter.Dump,
   func(string, int) (bool, error),
+  time.Time{
+    wall: 0,
+    ext: 63650361600,
+  },
 }

testdata/config_HomePackage.dump

@@ -16,4 +16,9 @@
   &20,
   litter.Dump,
   func(string, int) (bool, error),
+  time.Time{
+    wall: 0,
+    ext: 63650361600,
+    loc: nil,
+  },
 }

testdata/config_StrictGo.dump

@@ -16,4 +16,9 @@
   (func(v litter_test.IntAlias) *litter_test.IntAlias { return &v })(20),
   litter.Dump,
   func(string, int) (bool, error),
+  time.Time{
+    wall: 0,
+    ext: 63650361600,
+    loc: nil,
+  },
 }

testdata/config_StripPackageNames.dump

@@ -16,4 +16,9 @@
   &20,
   Dump,
   func(string, int) (bool, error),
+  Time{
+    wall: 0,
+    ext: 63650361600,
+    loc: nil,
+  },
 }