diff --git a/fjson/fielddata_test.go b/fjson/fielddata_test.go
index e8d034af..bb7551cd 100644
--- a/fjson/fielddata_test.go
+++ b/fjson/fielddata_test.go
@@ -148,6 +148,7 @@ func TestJSONExtractAndFill(t *testing.T) {
 	fieldDataExp, err := LoadFromJSONFile("./testdata/advancedform.json")
 	require.NoError(t, err)
 	jsonDataExp, err := fieldDataExp.JSON()
+	require.NoError(t, err)
 
 	// Check templates for equality.
 	require.Equal(t, jsonDataExp, jsonData)
@@ -184,6 +185,7 @@ func TestJSONExtractAndFill(t *testing.T) {
 	fieldDataExp, err = LoadFromJSON(bytes.NewReader(jsonBytes))
 	require.NoError(t, err)
 	jsonDataExp, err = fieldDataExp.JSON()
+	require.NoError(t, err)
 
 	// Fill test PDF form fields and write to buffer.
 	f, err := os.Open(inputFilePath)
@@ -212,6 +214,47 @@ func TestJSONExtractAndFill(t *testing.T) {
 	fieldData, err = LoadFromPDF(bytes.NewReader(buf.Bytes()))
 	require.NoError(t, err)
 	jsonData, err = fieldData.JSON()
+	require.NoError(t, err)
+
+	// Check field data for equality.
+	require.Equal(t, jsonDataExp, jsonData)
+}
+
+func TestJSONFillAndExtract(t *testing.T) {
+	// Read JSON fill data.
+	fieldDataExp, err := LoadFromJSONFile("./testdata/mixedfields.json")
+	require.NoError(t, err)
+	jsonDataExp, err := fieldDataExp.JSON()
+	require.NoError(t, err)
+
+	// Fill test PDF form fields and write to buffer.
+	f, err := os.Open("./testdata/mixedfields.pdf")
+	require.NoError(t, err)
+	defer f.Close()
+
+	reader, err := model.NewPdfReader(f)
+	require.NoError(t, err)
+
+	err = reader.AcroForm.Fill(fieldDataExp)
+	require.NoError(t, err)
+
+	var buf bytes.Buffer
+	writer := model.NewPdfWriter()
+	for i := range reader.PageList {
+		err := writer.AddPage(reader.PageList[i])
+		require.NoError(t, err)
+	}
+
+	err = writer.SetForms(reader.AcroForm)
+	require.NoError(t, err)
+	err = writer.Write(&buf)
+	require.NoError(t, err)
+
+	// Load field data from buffer.
+	fieldData, err := LoadFromPDF(bytes.NewReader(buf.Bytes()))
+	require.NoError(t, err)
+	jsonData, err := fieldData.JSON()
+	require.NoError(t, err)
 
 	// Check field data for equality.
 	require.Equal(t, jsonDataExp, jsonData)
diff --git a/fjson/testdata/mixedfields.json b/fjson/testdata/mixedfields.json
new file mode 100644
index 00000000..3ee55d32
--- /dev/null
+++ b/fjson/testdata/mixedfields.json
@@ -0,0 +1,94 @@
+[
+    {
+        "name": "Given Name Text Box",
+        "value": "Jane"
+    },
+    {
+        "name": "Family Name Text Box",
+        "value": "Doe"
+    },
+    {
+        "name": "House nr Text Box",
+        "value": "100"
+    },
+    {
+        "name": "Address 2 Text Box",
+        "value": "Generic Avenue"
+    },
+    {
+        "name": "Postcode Text Box",
+        "value": "11122"
+    },
+    {
+        "name": "Country Combo Box",
+        "value": "France"
+    },
+    {
+        "name": "Height Formatted Field",
+        "value": "175"
+    },
+    {
+        "name": "City Text Box",
+        "value": "Paris"
+    },
+    {
+        "name": "Driving License Check Box",
+        "value": "Yes",
+        "options": [
+            "Yes",
+            "Off"
+        ]
+    },
+    {
+        "name": "Favourite Colour List Box",
+        "value": "Yellow"
+    },
+    {
+        "name": "Language 1 Check Box",
+        "value": "Yes",
+        "options": [
+            "Yes",
+            "Off"
+        ]
+    },
+    {
+        "name": "Language 2 Check Box",
+        "value": "Off",
+        "options": [
+            "Yes",
+            "Off"
+        ]
+    },
+    {
+        "name": "Language 3 Check Box",
+        "value": "Yes",
+        "options": [
+            "Yes",
+            "Off"
+        ]
+    },
+    {
+        "name": "Language 4 Check Box",
+        "value": "Off",
+        "options": [
+            "Yes",
+            "Off"
+        ]
+    },
+    {
+        "name": "Language 5 Check Box",
+        "value": "Yes",
+        "options": [
+            "Yes",
+            "Off"
+        ]
+    },
+    {
+        "name": "Gender List Box",
+        "value": "Woman"
+    },
+    {
+        "name": "Address 1 Text Box",
+        "value": "Generic Street"
+    }
+]
diff --git a/fjson/testdata/mixedfields.pdf b/fjson/testdata/mixedfields.pdf
new file mode 100644
index 00000000..72d0d21d
Binary files /dev/null and b/fjson/testdata/mixedfields.pdf differ