Add form fill render tests (#387)

* Add form fill render tests

* Update Jenkins file

Jenkinsfile

@@ -7,6 +7,7 @@ node {
     env.PATH="${root}/bin:${env.GOBIN}:${env.PATH}"
     env.UNIDOC_EXTRACT_FORCETEST="1"
     env.UNIDOC_E2E_FORCE_TESTS="1"
+    env.UNIDOC_RENDERTEST_FORMFILL_FORCETEST="1"
     env.UNIDOC_EXTRACT_TESTDATA="/home/jenkins/corpus/unidoc-extractor-testdata"
     env.UNIDOC_RENDERTEST_BASELINE_PATH="/home/jenkins/corpus/unidoc-creator-render-testdata-upd2"
     env.UNIDOC_PASSTHROUGH_TESTDATA="/home/jenkins/corpus/unidoc-e2e-testdata"
@@ -15,6 +16,8 @@ node {
     env.UNIDOC_EXTRACT_IMAGES_TESTDATA="/home/jenkins/corpus/unidoc-e2e-extract-images-testdata"
     env.UNIDOC_JBIG2_TESTDATA="/home/jenkins/corpus/jbig2-testdata"
     env.UNIDOC_FDFMERGE_TESTDATA="/home/jenkins/corpus/fdfmerge-testdata"
+    env.UNIDOC_RENDERTEST_FORMFILL_TESTDATA="/home/jenkins/corpus/unidoc-form-fill-render-testdata"
+    env.UNIDOC_RENDERTEST_FORMFILL_BASELINE="/home/jenkins/corpus/unidoc-form-fill-render-baseline"
     env.UNIDOC_GS_BIN_PATH="/usr/bin/gs"
     env.CGO_ENABLED="0"
 
@@ -95,7 +98,7 @@ node {
 
             // Use replace directive to use disk version of unipdf.
             sh 'echo "replace github.com/unidoc/unipdf/v3 => ../unipdf" >>go.mod'
-            
+
             // Dependencies for examples.
             sh './build_examples.sh'
         }

annotator/form_fill_test.go

@@ -0,0 +1,179 @@
+/*
+ * This file is subject to the terms and conditions defined in
+ * file 'LICENSE.md', which is part of this source code package.
+ */
+
+package annotator
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/unidoc/unipdf/v3/common"
+	"github.com/unidoc/unipdf/v3/fjson"
+	"github.com/unidoc/unipdf/v3/model"
+
+	"github.com/unidoc/unipdf/v3/internal/testutils"
+)
+
+func init() {
+	common.SetLogger(common.NewConsoleLogger(common.LogLevelDebug))
+}
+
+// TestFormFillRender tests the form fill/flatten process using the test data
+// in a provided corpus directory. The corpus directory should contain
+// (name.pdf, name.json) pairs of files. The filled output files are rendered
+// to PNG images and compared to counterpart golden images found in a provided
+// baseline directory.
+// The test input parameters are specified through environment variables:
+//  - UNIDOC_RENDERTEST_FORMFILL_TESTDATA
+//    The test corpus directory. If not provided, the test is skipped.
+//  - UNIDOC_RENDERTEST_FORMFILL_BASELINE
+//    The baseline corpus directory. If not provided, the test is skipped.
+//  - UNIDOC_RENDERTEST_FORMFILL_FORCETEST
+//    Set to "1" to force the test to run. If enabled, the test data and
+//    baseline corpus directories are required.
+//  - UNIDOC_RENDERTEST_FORMFILL_SAVE_BASELINE
+//    Set to "1" to save rendered images of new input files to the
+//    baseline directory.
+func TestFormFillRender(t *testing.T) {
+	// Read environment variables.
+	forceRun := os.Getenv("UNIDOC_RENDERTEST_FORMFILL_FORCETEST") == "1"
+
+	renderInputPath := os.Getenv("UNIDOC_RENDERTEST_FORMFILL_TESTDATA")
+	if renderInputPath == "" {
+		if forceRun {
+			t.Fatalf("UNIDOC_RENDERTEST_FORMFILL_TESTDATA not set")
+		}
+		t.Skip("skipping render tests; set UNIDOC_RENDERTEST_FORMFILL_TESTDATA to run")
+	}
+
+	renderBaselinePath := os.Getenv("UNIDOC_RENDERTEST_FORMFILL_BASELINE")
+	if renderBaselinePath == "" {
+		if forceRun {
+			t.Fatalf("UNIDOC_RENDERTEST_FORMFILL_BASELINE not set")
+		}
+		t.Skip("skipping render tests; set UNIDOC_RENDERTEST_FORMFILL_BASELINE to run")
+	}
+	saveBaseline := os.Getenv("UNIDOC_RENDERTEST_FORMFILL_SAVE_BASELINE") == "1"
+
+	// Get input file list.
+	type formFillInput struct {
+		filename string
+		pdfPath  string
+		jsonPath string
+	}
+
+	files, err := ioutil.ReadDir(renderInputPath)
+	require.NoError(t, err)
+
+	var fillInputs []*formFillInput
+	for _, file := range files {
+		basename := file.Name()
+
+		ext := filepath.Ext(basename)
+		if ext != ".json" {
+			continue
+		}
+		filename := strings.TrimSuffix(basename, ext)
+
+		fillInputs = append(fillInputs, &formFillInput{
+			filename: filename,
+			pdfPath:  filepath.Join(renderInputPath, filename+".pdf"),
+			jsonPath: filepath.Join(renderInputPath, basename),
+		})
+	}
+
+	lenFillInputs := len(fillInputs)
+	if lenFillInputs == 0 {
+		t.Skip("skipping render tests; no input files found")
+	}
+
+	// Create a temporary folder and clean up after the tests finish.
+	tempDir, err := ioutil.TempDir("", "unidoc_form_fill")
+	require.NoError(t, err)
+	defer os.RemoveAll(tempDir)
+
+	// Fill and render input files.
+	appearance := FieldAppearance{RegenerateTextFields: true}
+	style := appearance.Style()
+	style.BorderSize = 1
+	style.AutoFontSizeFraction = 0.70
+	appearance.SetStyle(style)
+
+	for i, fi := range fillInputs {
+		t.Logf("(%d/%d) Running render tests for file %s", i+1, lenFillInputs, fi.pdfPath)
+
+		fillAndRender := func(flatten, regenerate bool) {
+			outputPath := fi.filename + "_fill"
+			if flatten {
+				outputPath += "_flatten"
+			}
+			if regenerate {
+				outputPath += "_regenerate"
+			}
+			outputPath = filepath.Join(tempDir, outputPath+".pdf")
+			appearance.OnlyIfMissing = !regenerate
+
+			testWriteFilledForm(t, fi.pdfPath, fi.jsonPath, outputPath, flatten, appearance)
+			testutils.RunRenderTest(t, outputPath, tempDir, renderBaselinePath, saveBaseline)
+		}
+
+		// Fill, regenerate appearance only if missing.
+		fillAndRender(false, false)
+
+		// Fill, flatten, regenerate appearance only if missing.
+		fillAndRender(true, false)
+
+		// Fill, regenerate appearance.
+		fillAndRender(false, true)
+
+		// Fill, flatten, regenerate appearance.
+		fillAndRender(true, true)
+	}
+}
+
+func testWriteFilledForm(t *testing.T, pdfPath, jsonPath, outputPath string,
+	flatten bool, appearance model.FieldAppearanceGenerator) {
+	// Load JSON template.
+	jsonData, err := fjson.LoadFromJSONFile(jsonPath)
+	require.NoError(t, err)
+
+	// Open input file.
+	inputFile, err := os.Open(pdfPath)
+	require.NoError(t, err)
+	defer inputFile.Close()
+
+	// Create reader.
+	reader, err := model.NewPdfReader(inputFile)
+	require.NoError(t, err)
+	require.NotNil(t, reader.AcroForm)
+
+	// Fill form fields.
+	require.NoError(t, reader.AcroForm.FillWithAppearance(jsonData, appearance))
+
+	// Flatten form fields.
+	if flatten {
+		require.NoError(t, reader.FlattenFields(true, appearance))
+	}
+
+	// Create writer.
+	writer := model.NewPdfWriter()
+	writer.SetForms(reader.AcroForm)
+
+	for _, page := range reader.PageList {
+		require.NoError(t, writer.AddPage(page))
+	}
+
+	// Write output file.
+	outputFile, err := os.Create(outputPath)
+	require.NoError(t, err)
+	defer outputFile.Close()
+
+	require.NoError(t, writer.Write(outputFile))
+}