feat: render Markdown, mathematics and Mermaid diagrams server-side

scriptorium_test.go

@@ -0,0 +1,88 @@
+// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
+// SPDX-License-Identifier: MIT
+
+package scriptorium
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestSupportedDiagram(t *testing.T) {
+	supported := []string{"flowchart", "graph", "sequenceDiagram"}
+	for _, kind := range supported {
+		if !SupportedDiagram(kind) {
+			t.Errorf("SupportedDiagram(%q) = false, want true", kind)
+		}
+	}
+	refused := []string{"", "stateDiagram-v2", "pie", "gantt", "classDiagram", "Flowchart"}
+	for _, kind := range refused {
+		if SupportedDiagram(kind) {
+			t.Errorf("SupportedDiagram(%q) = true, want false", kind)
+		}
+	}
+}
+
+func TestRender(t *testing.T) {
+	got := string(Render([]byte("# Title\n\nHello *world*.\n")))
+	want := "<h1>Title</h1>\n<p>Hello <em>world</em>.</p>\n"
+	if got != want {
+		t.Errorf("Render = %q, want %q", got, want)
+	}
+}
+
+func TestRenderDeterministic(t *testing.T) {
+	source := []byte("- one\n- two\n\n```go\nfmt.Println(1)\n```\n")
+	first := Render(source)
+	for range 5 {
+		if next := Render(source); !bytes.Equal(first, next) {
+			t.Fatal("Render of the same source differs between calls")
+		}
+	}
+}
+
+func TestRenderMath(t *testing.T) {
+	got := string(RenderMath([]byte(`\frac{1}{2}`)))
+	want := `<math xmlns="http://www.w3.org/1998/Math/MathML"><mfrac><mn>1</mn><mn>2</mn></mfrac></math>`
+	if got != want {
+		t.Errorf("RenderMath = %s, want %s", got, want)
+	}
+}
+
+func TestRenderMathDisplay(t *testing.T) {
+	got := string(RenderMathDisplay([]byte("x")))
+	want := `<math xmlns="http://www.w3.org/1998/Math/MathML" display="block"><mi>x</mi></math>`
+	if got != want {
+		t.Errorf("RenderMathDisplay = %s, want %s", got, want)
+	}
+}
+
+func TestRenderDiagram(t *testing.T) {
+	out, err := RenderDiagram([]byte("flowchart TD\n  A[Start] --> B[End]\n"))
+	if err != nil {
+		t.Fatalf("render: %v", err)
+	}
+	if !bytes.HasPrefix(out, []byte(`<svg xmlns="http://www.w3.org/2000/svg"`)) {
+		t.Errorf("RenderDiagram = %s", out)
+	}
+}
+
+func TestRenderDiagramRefuses(t *testing.T) {
+	if _, err := RenderDiagram([]byte("pie\n  \"a\": 1\n")); err == nil {
+		t.Error("expected a refusal for an unsupported diagram type")
+	}
+}
+
+func TestRenderDiagramDeterministic(t *testing.T) {
+	source := []byte("sequenceDiagram\n  A->>B: hello\n  B-->>A: bye\n")
+	first, err := RenderDiagram(source)
+	if err != nil {
+		t.Fatalf("render: %v", err)
+	}
+	for range 5 {
+		next, err := RenderDiagram(source)
+		if err != nil || !bytes.Equal(first, next) {
+			t.Fatal("RenderDiagram of the same source differs between calls")
+		}
+	}
+}