From 9bbbc455e35f046a33301fbe8f973f2b2a288e93 Mon Sep 17 00:00:00 2001
From: William Poussier <william.poussier@gmail.com>
Date: Mon, 17 Jun 2024 15:35:47 +0200
Subject: [PATCH] test: small improvements to coverage

---
 .golangci.yaml  |  2 +-
 apply_test.go   | 13 ++++++++++++-
 compare.go      |  7 ++-----
 compare_test.go | 49 ++++++++++++++++++++++++++++++++++++++++++++++++-
 equal.go        |  8 ++------
 5 files changed, 65 insertions(+), 14 deletions(-)

diff --git a/.golangci.yaml b/.golangci.yaml
index 9c6e21c..bf977ae 100644
--- a/.golangci.yaml
+++ b/.golangci.yaml
@@ -1,5 +1,5 @@
 run:
-  go: "1.21"
+  go: "1.22"
   timeout: 10m
 linters:
   disable-all: true
diff --git a/apply_test.go b/apply_test.go
index f31de3c..5015895 100644
--- a/apply_test.go
+++ b/apply_test.go
@@ -1,6 +1,8 @@
 package jsondiff
 
-import "testing"
+import (
+	"testing"
+)
 
 func Test_toDotPath(t *testing.T) {
 	for _, tc := range []struct {
@@ -80,3 +82,12 @@ func Test_isArrayIndex(t *testing.T) {
 		}
 	}
 }
+
+func TestPatch_apply_invalidJSON(t *testing.T) {
+	badJSON := []byte(`{"example":2:]}}`)
+
+	var p Patch
+	if _, err := p.apply(badJSON, true); err == nil {
+		t.Errorf("expected non-nil error")
+	}
+}
diff --git a/compare.go b/compare.go
index debc3b0..19a7c98 100644
--- a/compare.go
+++ b/compare.go
@@ -34,11 +34,8 @@ func CompareWithoutMarshal(source, target interface{}, opts ...Option) (patch Pa
 
 	defer func() {
 		if r := recover(); r != nil {
-			if e, ok := r.(invalidJSONTypeError); ok {
-				err = e
-			} else {
-				err = fmt.Errorf("recovered from panic: %q", r)
-			}
+			e := r.(invalidJSONTypeError)
+			err = fmt.Errorf("jsondiff: invalid json type: %T", e.t)
 			patch = nil
 		}
 	}()
diff --git a/compare_test.go b/compare_test.go
index 0dabe39..13b67e3 100644
--- a/compare_test.go
+++ b/compare_test.go
@@ -1,6 +1,7 @@
 package jsondiff
 
 import (
+	"bytes"
 	"encoding/json"
 	"errors"
 	"testing"
@@ -31,7 +32,7 @@ func Test_marshalUnmarshal_invalid_JSON(t *testing.T) {
 	})
 }
 
-func TestCompareWithoutMarshal(t *testing.T) {
+func TestCompareWithoutMarshal_error(t *testing.T) {
 	type custom struct {
 		foo string
 		bar int
@@ -42,3 +43,49 @@ func TestCompareWithoutMarshal(t *testing.T) {
 	}
 	t.Log(err)
 }
+
+type skip struct{}
+
+var skipBytes = []byte("skip")
+
+func Test_compare_marshaling_error(t *testing.T) {
+	e := errors.New("")
+
+	d := Differ{opts: options{
+		marshal: func(a any) ([]byte, error) {
+			if _, ok := a.(skip); ok {
+				return skipBytes, nil
+			}
+			return nil, e
+		},
+		unmarshal: func(b []byte, _ any) error {
+			if bytes.Equal(b, skipBytes) {
+				return nil
+			}
+			return e
+		},
+	}}
+	if _, err := compare(&d, nil, nil); !errors.Is(err, e) {
+		t.Errorf("expected non-nil error")
+	}
+	if _, err := compare(&d, skip{}, nil); !errors.Is(err, e) {
+		t.Errorf("expected non-nil error")
+	}
+}
+
+func Test_compareJSON_marshaling_error(t *testing.T) {
+	e := errors.New("")
+
+	unmarshalFn := func(b []byte, _ any) error {
+		if bytes.Equal(b, skipBytes) {
+			return nil
+		}
+		return e
+	}
+	if _, err := compareJSON(nil, nil, nil, unmarshalFn); !errors.Is(err, e) {
+		t.Errorf("expected non-nil error")
+	}
+	if _, err := compareJSON(nil, []byte("skip"), nil, unmarshalFn); !errors.Is(err, e) {
+		t.Errorf("expected non-nil error")
+	}
+}
diff --git a/equal.go b/equal.go
index 9bcce55..21d16f5 100644
--- a/equal.go
+++ b/equal.go
@@ -2,7 +2,6 @@ package jsondiff
 
 import (
 	"encoding/json"
-	"fmt"
 	"strconv"
 )
 
@@ -10,10 +9,6 @@ type invalidJSONTypeError struct {
 	t any
 }
 
-func (e invalidJSONTypeError) Error() string {
-	return fmt.Sprintf("jsondiff: invalid json type: %T", e.t)
-}
-
 // jsonValueType represents the type of JSON value.
 // It follows the types of values stored by json.Unmarshal
 // in interface values.
@@ -122,8 +117,9 @@ func deepEqualValue(src, tgt interface{}) bool {
 			}
 		}
 		return true
+	default:
+		panic("unexpected json type")
 	}
-	return false
 }
 
 var jsonTypeNames = []string{