latexgrambot: inline LaTeX bot for Telegram in Go
Renders LaTeX expressions into PNG pictures, PDF documents and native Telegram rich text messages, entirely locally with TeX Live and poppler. - Chat mode with /image, /pdf, /rich plus per-user preamble and DPI - Inline mode delivering picture, PDF and rich text results - Broad default package set preloaded into a TeX format at image build - MongoDB persistence: settings, users, groups, render statistics - Private S3-compatible bucket with short-lived presigned URLs - OpenTelemetry traces over OTLP - Kubernetes manifests and Argo CD application, Docker Compose, GitHub Actions CI, BSD 3-Clause license
This commit is contained in:
corrado.mulas
243
internal/render/render_test.go
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243
internal/render/render_test.go
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package render
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import (
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"bytes"
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"context"
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"image"
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_ "image/png"
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"os/exec"
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"strings"
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"testing"
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"time"
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)
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func TestBuildDocument(t *testing.T) {
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t.Run("default preamble", func(t *testing.T) {
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doc := buildDocument("", `$x^2$`)
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if !strings.Contains(doc, "\\documentclass[preview,varwidth,border=4pt]{standalone}") {
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t.Errorf("missing document class:\n%s", doc)
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}
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if !strings.Contains(doc, defaultPackages) {
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t.Errorf("missing default packages:\n%s", doc)
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}
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if !strings.Contains(doc, "\\begin{document}\n$x^2$\n\\end{document}") {
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t.Errorf("expression not placed in the document body:\n%s", doc)
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}
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})
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t.Run("custom preamble extends packages", func(t *testing.T) {
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doc := buildDocument(`\usepackage{chemist}`, `H_2O`)
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if !strings.Contains(doc, defaultPackages) {
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t.Errorf("default packages missing:\n%s", doc)
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}
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if !strings.Contains(doc, "\\usepackage{chemist}") {
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t.Errorf("custom preamble missing:\n%s", doc)
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}
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if !strings.Contains(doc, "\\begin{document}\nH_2O\n\\end{document}") {
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t.Errorf("expression not placed in the document body:\n%s", doc)
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}
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})
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}
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func TestExtractError(t *testing.T) {
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log := strings.Join([]string{
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"This is pdfTeX, Version 3.141592653-2.6-1.40.26",
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"! Undefined control sequence.",
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"l.4 \\begin{document}",
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" \\badcommand",
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"",
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"! LaTeX Error: File `missing.sty' not found.",
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"l.5 \\usepackage{missing}",
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}, "\n")
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excerpt := extractError(log)
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if !strings.Contains(excerpt, "! Undefined control sequence.") {
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t.Errorf("missing first error line in %q", excerpt)
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}
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if !strings.Contains(excerpt, "l.4 \\begin{document}") {
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t.Errorf("missing context line in %q", excerpt)
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}
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if strings.Contains(excerpt, "missing.sty") {
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t.Errorf("second error must not be reported with -halt-on-error behavior: %q", excerpt)
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}
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}
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func TestExtractErrorWithoutErrorLine(t *testing.T) {
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excerpt := extractError("some unrelated log content")
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if !strings.Contains(excerpt, "without an explicit error") {
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t.Errorf("unexpected excerpt: %q", excerpt)
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}
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}
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func TestRenderIntegration(t *testing.T) {
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if _, err := exec.LookPath("pdflatex"); err != nil {
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t.Skip("pdflatex not installed")
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}
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if _, err := exec.LookPath("pdftoppm"); err != nil {
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t.Skip("pdftoppm not installed")
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}
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r := New("pdflatex", "pdftoppm", 30*time.Second, 2, "")
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ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
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defer cancel()
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result, err := r.Render(ctx, "", `$\int_0^\infty e^{-x^2}\,dx = \frac{\sqrt{\pi}}{2}$`, 150)
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if err != nil {
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t.Fatalf("render failed: %v", err)
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}
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if len(result.PNG) == 0 {
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t.Fatal("empty PNG")
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}
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if !strings.HasPrefix(string(result.PNG), "\x89PNG") {
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t.Fatal("output is not a PNG file")
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}
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width, height, err := pngSizeBytes(result.PNG)
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if err != nil {
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t.Fatalf("decode png size: %v", err)
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}
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if width < minRenderedSide && height < minRenderedSide {
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t.Errorf("png is %dx%d, want the smallest side at least %d", width, height, minRenderedSide)
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}
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if width > maxRenderedSide || height > maxRenderedSide {
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t.Errorf("png is %dx%d, want no side beyond %d", width, height, maxRenderedSide)
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}
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if len(result.PDF) == 0 || !strings.HasPrefix(string(result.PDF), "%PDF") {
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t.Fatal("output is not a PDF file")
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}
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if len(result.JPEG) == 0 || !strings.HasPrefix(string(result.JPEG), "\xff\xd8") {
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t.Fatal("output is not a JPEG file")
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}
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linked, err := r.Render(ctx, "", `\hypertarget{details}{Details}\par\hyperlink{details}{Go to details}`, 150)
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if err != nil {
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t.Fatalf("hyperlink render failed: %v", err)
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}
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if len(linked.PDF) == 0 || len(linked.PNG) == 0 || len(linked.JPEG) == 0 {
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t.Fatal("hyperlink render returned an empty format")
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}
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}
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func pngSizeBytes(data []byte) (int, int, error) {
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config, _, err := image.DecodeConfig(bytes.NewReader(data))
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if err != nil {
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return 0, 0, err
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}
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return config.Width, config.Height, nil
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}
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func TestRenderErrorIntegration(t *testing.T) {
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if _, err := exec.LookPath("pdflatex"); err != nil {
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t.Skip("pdflatex not installed")
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}
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r := New("pdflatex", "pdftoppm", 30*time.Second, 2, "")
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ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
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defer cancel()
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_, err := r.Render(ctx, "", `\undefinedcommandxyz`, 150)
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latexErr, ok := err.(*LatexError)
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if !ok {
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t.Fatalf("expected *LatexError, got %T: %v", err, err)
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}
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if !strings.Contains(latexErr.Excerpt, "! Undefined control sequence") {
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t.Errorf("unexpected excerpt: %q", latexErr.Excerpt)
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}
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}
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func TestRenderPreWrapsBareMath(t *testing.T) {
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if _, err := exec.LookPath("pdflatex"); err != nil {
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t.Skip("pdflatex not installed")
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}
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r := New("pdflatex", "pdftoppm", 30*time.Second, 2, "")
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ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
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defer cancel()
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// Bare math is wrapped up front, so a single compile succeeds.
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result, err := r.Render(ctx, "", `\int_0^1 x\,dx`, 150)
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if err != nil {
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t.Fatalf("render failed: %v", err)
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}
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if len(result.PNG) == 0 || len(result.PDF) == 0 {
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t.Fatal("empty output")
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}
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}
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func TestRenderRetriesMissingDollarForMath(t *testing.T) {
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if _, err := exec.LookPath("pdflatex"); err != nil {
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t.Skip("pdflatex not installed")
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}
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r := New("pdflatex", "pdftoppm", 30*time.Second, 2, "")
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ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
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defer cancel()
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// A math environment is not pre-wrapped; the compile fails once with
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// "Missing $ inserted" and the retry wraps the whole expression.
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result, err := r.Render(ctx, "", "\\begin{matrix}a&b\\\\c&d\\end{matrix} \\int_0^1 x\\,dx", 150)
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if err != nil {
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t.Fatalf("render failed: %v", err)
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}
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if len(result.PNG) == 0 || len(result.PDF) == 0 {
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t.Fatal("empty output")
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}
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}
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func TestRenderNoRetryForMixedInput(t *testing.T) {
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if _, err := exec.LookPath("pdflatex"); err != nil {
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t.Skip("pdflatex not installed")
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}
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r := New("pdflatex", "pdftoppm", 30*time.Second, 2, "")
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ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
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defer cancel()
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// Mixed text with a math-only command inside is not retried: the error
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// is reported to the user as-is.
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_, err := r.Render(ctx, "", "\\begin{itemize}\\item \\int\\end{itemize}", 150)
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latexErr, ok := err.(*LatexError)
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if !ok {
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t.Fatalf("expected *LatexError, got %T: %v", err, err)
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}
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if !strings.Contains(latexErr.Excerpt, "Missing $ inserted") {
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t.Errorf("unexpected excerpt: %q", latexErr.Excerpt)
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}
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}
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func TestDefaultPreamble(t *testing.T) {
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preamble := DefaultPreamble()
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for _, fragment := range []string{
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"\\documentclass[preview,varwidth,border=4pt]{standalone}",
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"\\usepackage{amsmath}",
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"\\usepackage{tikz}",
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"\\endofdump",
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} {
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if !strings.Contains(preamble, fragment) {
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t.Errorf("preamble missing %q", fragment)
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}
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}
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}
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func TestNormalizeExpression(t *testing.T) {
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cases := map[string]string{
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`\mathbb{ R }`: `\mathbb{ R }`,
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`$\mathbb{R}$`: `$\mathbb{R}$`,
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`$$x^2 + y^2$$`: `$$x^2 + y^2$$`,
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`\[ \frac{1}{2} \]`: `\[ \frac{1}{2} \]`,
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`\(a+b\)`: `\(a+b\)`,
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" x ": `x`,
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`\begin{align} a &= b \\ c &= d \end{align}`: `\begin{align} a &= b \\ c &= d \end{align}`,
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}
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for input, want := range cases {
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got, err := normalizeExpression(input)
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if err != nil {
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t.Fatalf("normalizeExpression(%q): %v", input, err)
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}
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if got != want {
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t.Fatalf("normalizeExpression(%q) = %q, want %q", input, got, want)
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}
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}
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if _, err := normalizeExpression(`\input{/etc/passwd}`); err == nil {
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t.Fatal("dangerous command was accepted")
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}
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if _, err := normalizeExpression(" "); err == nil {
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t.Fatal("empty expression was accepted")
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}
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}
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