test: improve coverage of side cases

equal_test.go

@@ -92,6 +92,44 @@ func Test_jsonTypeSwitch(t *testing.T) {
 	}
 }
 
+func Test_deepEqualValue(t *testing.T) {
+	for _, tt := range []struct {
+		src, tgt interface{}
+		equal    bool
+	}{
+		{
+			nil,
+			nil,
+			true,
+		},
+		{
+			"foobar",
+			"foobar",
+			true,
+		},
+		{
+			true,
+			false,
+			false,
+		},
+		{
+			3.14,
+			3.14,
+			true,
+		},
+		{
+			json.Number("42.69"),
+			json.Number("69.42"),
+			false,
+		},
+	} {
+		ok := deepEqualValue(tt.src, tt.tgt)
+		if ok != tt.equal {
+			t.Errorf("got %t, want %t", ok, tt.equal)
+		}
+	}
+}
+
 func Test_deepEqual_invalid_type(t *testing.T) {
 	defer func() {
 		if err := recover(); err == nil {

operation_test.go

@@ -2,7 +2,7 @@ package jsondiff
 
 import "testing"
 
-func TestOperationMarshalJSON(t *testing.T) {
+func TestOperation_MarshalJSON(t *testing.T) {
 	for _, tc := range []struct {
 		Op  Operation
 		Out string // marshaled output
@@ -101,7 +101,7 @@ func TestOperationMarshalJSON(t *testing.T) {
 	}
 }
 
-func TestPatchString(t *testing.T) {
+func TestPatch_String(t *testing.T) {
 	patch := Patch{
 		{
 			Type:  OperationReplace,
@@ -129,7 +129,7 @@ func TestPatchString(t *testing.T) {
 	}
 }
 
-func TestNilPatchString(t *testing.T) {
+func TestPatch_String_nil(t *testing.T) {
 	p := new(Patch)
 	s := p.String()
 
@@ -138,6 +138,23 @@ func TestNilPatchString(t *testing.T) {
 	}
 }
 
+func TestPatch_jsonLength(t *testing.T) {
+	t.Run("empty", func(t *testing.T) {
+		p := new(Patch)
+		l := p.jsonLength()
+		if l != 0 {
+			t.Error("expected zero length for empty patch")
+		}
+	})
+	t.Run("nil", func(t *testing.T) {
+		var p *Patch
+		l := p.jsonLength()
+		if l != 0 {
+			t.Error("expected zero length for nil patch")
+		}
+	})
+}
+
 func typeNilIface() interface{} {
 	var i *int
 	var p interface{}