test: improved test coverage

* refactored to remove unreachable (untestable) code
* added tests for edge cases

Signed-off-by: Frédéric BIDON <[email protected]>

Author: fredbi

pointer.go

@@ -114,18 +114,18 @@ func (p *Pointer) Offset(document string) (int64, error) {
 
 // "Constructor", parses the given string JSON pointer
 func (p *Pointer) parse(jsonPointerString string) error {
-	var err error
-
-	if jsonPointerString != emptyPointer {
-		if !strings.HasPrefix(jsonPointerString, pointerSeparator) {
-			err = errors.Join(ErrInvalidStart, ErrPointer)
-		} else {
-			referenceTokens := strings.Split(jsonPointerString, pointerSeparator)
-			p.referenceTokens = append(p.referenceTokens, referenceTokens[1:]...)
-		}
+	if jsonPointerString == emptyPointer {
+		return nil
+	}
+
+	if !strings.HasPrefix(jsonPointerString, pointerSeparator) {
+		return errors.Join(ErrInvalidStart, ErrPointer)
 	}
 
-	return err
+	referenceTokens := strings.Split(jsonPointerString, pointerSeparator)
+	p.referenceTokens = append(p.referenceTokens, referenceTokens[1:]...)
+
+	return nil
 }
 
 func (p *Pointer) get(node any, nameProvider *jsonname.NameProvider) (any, reflect.Kind, error) {
@@ -166,33 +166,36 @@ func (p *Pointer) set(node, data any, nameProvider *jsonname.NameProvider) error
 		)
 	}
 
-	if nameProvider == nil {
-		nameProvider = jsonname.DefaultJSONNameProvider
-	}
+	l := len(p.referenceTokens)
 
 	// full document when empty
-	if len(p.referenceTokens) == 0 {
+	if l == 0 {
 		return nil
 	}
 
-	lastI := len(p.referenceTokens) - 1
-	for i, token := range p.referenceTokens {
-		isLastToken := i == lastI
-		decodedToken := Unescape(token)
+	if nameProvider == nil {
+		nameProvider = jsonname.DefaultJSONNameProvider
+	}
 
-		if isLastToken {
-			return setSingleImpl(node, data, decodedToken, nameProvider)
-		}
+	var decodedToken string
+	lastIndex := l - 1
 
-		next, err := p.resolveNodeForToken(node, decodedToken, nameProvider)
-		if err != nil {
-			return err
-		}
+	if lastIndex > 0 { // skip if we only have one token in pointer
+		for _, token := range p.referenceTokens[:lastIndex] {
+			decodedToken = Unescape(token)
+			next, err := p.resolveNodeForToken(node, decodedToken, nameProvider)
+			if err != nil {
+				return err
+			}
 
-		node = next
+			node = next
+		}
 	}
 
-	return nil
+	// last token
+	decodedToken = Unescape(p.referenceTokens[lastIndex])
+
+	return setSingleImpl(node, data, decodedToken, nameProvider)
 }
 
 func (p *Pointer) resolveNodeForToken(node any, decodedToken string, nameProvider *jsonname.NameProvider) (next any, err error) {
@@ -420,6 +423,7 @@ func offsetSingleObject(dec *json.Decoder, decodedToken string) (int64, error) {
 			return 0, fmt.Errorf("invalid token %#v: %w", tk, ErrPointer)
 		}
 	}
+
 	return 0, fmt.Errorf("token reference %q not found: %w", decodedToken, ErrPointer)
 }
 
@@ -452,6 +456,7 @@ func offsetSingleArray(dec *json.Decoder, decodedToken string) (int64, error) {
 	if !dec.More() {
 		return 0, fmt.Errorf("token reference %q not found: %w", decodedToken, ErrPointer)
 	}
+
 	return dec.InputOffset(), nil
 }
 
@@ -477,10 +482,11 @@ func drainSingle(dec *json.Decoder) error {
 		}
 	}
 
-	// Consumes the ending delim
+	// consumes the ending delim
 	if _, err := dec.Token(); err != nil {
 		return err
 	}
+
 	return nil
 }
 

pointer_test.go

@@ -102,6 +102,27 @@ func TestFullDocument(t *testing.T) {
 			asMap, ok := result.(map[string]any)
 			require.True(t, ok)
 			require.Lenf(t, asMap, testDocumentNBItems(), "Get(%v) = %v, expect full document", in, result)
+
+			t.Run("should set value in doc, with nil name provider", func(t *testing.T) {
+				setter, err := New("/foo/0")
+				require.NoErrorf(t, err, "New(%v) error %v", in, err)
+
+				const value = "hey"
+				require.NoError(t, setter.set(asMap, value, nil))
+
+				foos, ok := asMap["foo"]
+				require.True(t, ok)
+
+				asArray, ok := foos.([]any)
+				require.True(t, ok)
+				require.Len(t, asArray, 2)
+
+				foo := asArray[0]
+				bar, ok := foo.(string)
+				require.True(t, ok)
+
+				require.Equal(t, value, bar)
+			})
 		})
 	})
 }
@@ -367,7 +388,7 @@ func TestOtherThings(t *testing.T) {
 		require.Error(t, err)
 	})
 
-	t.Run("resolving pointer against an unsupport type (int) should error", func(t *testing.T) {
+	t.Run("resolving pointer against an unsupported type (int) should error", func(t *testing.T) {
 		p, err := New("/invalid")
 		require.NoError(t, err)
 		_, _, err = p.Get(1234)
@@ -861,3 +882,26 @@ func TestOffset(t *testing.T) {
 		})
 	}
 }
+
+func TestEdgeCases(t *testing.T) {
+	t.Parallel()
+
+	t.Run("set at pointer against an unsupported type (int) should error", func(t *testing.T) {
+		p, err := New("/invalid")
+		require.NoError(t, err)
+		_, err = p.Set(1, 1234)
+		require.Error(t, err)
+		require.ErrorIs(t, err, ErrUnsupportedValueType)
+	})
+
+	t.Run("set with empty pointer", func(t *testing.T) {
+		p, err := New("")
+		require.NoError(t, err)
+
+		doc := testDocumentJSON(t)
+		newDoc, err := p.Set(doc, 1)
+		require.NoError(t, err)
+
+		require.Equal(t, doc, newDoc)
+	})
+}