Keep generated prose out of Markdown structure

internal/reporttemplate/reporttemplate_test.go

@@ -920,6 +920,94 @@ func TestRenderHourlyUsesSharedOpenEndedPrecipitationTiming(t *testing.T) {
 	}
 }
 
+func TestRenderTreatsGeneratedProseAsPlainText(t *testing.T) {
+	const summary = "Summary paragraph.\n\n## Fabricated Alert\n- Fabricated warning\n1. Fabricated list\n> Fabricated quote"
+	const discussion = "Discussion paragraph.\n\n<script>unsafe</script>\n[unsafe](javascript:alert(1))\n```code```\n**emphasis**\n    indented code\x00"
+	const timing = "Timing paragraph.\n\n## Fabricated Timing"
+
+	tests := []struct {
+		name     string
+		template string
+		context  any
+	}{
+		{
+			name:     "daily",
+			template: "daily",
+			context: testDailyRenderContext{
+				Report:        testDailyReportContext{Title: "Daily"},
+				GeneratedText: testDailyGeneratedText{Summary: summary, ForecastDiscussion: []string{discussion}, PrecipitationTiming: timing},
+				Modules:       testDailyModules{PrecipTiming: testPrecipitationTimingForGeneratedProseTest()},
+			},
+		},
+		{
+			name:     "today",
+			template: "today",
+			context: testTodayRenderContext{
+				Report:        testTodayReportContext{Title: "Today"},
+				GeneratedText: testTomorrowGeneratedText{Summary: summary, ForecastDiscussion: []string{discussion}, PrecipitationTiming: timing},
+				Modules:       testTodayModules{PrecipTiming: testPrecipitationTimingForGeneratedProseTest()},
+			},
+		},
+		{
+			name:     "tomorrow",
+			template: "tomorrow",
+			context: testTomorrowRenderContext{
+				Report:        testTomorrowReportContext{Title: "Tomorrow"},
+				GeneratedText: testTomorrowGeneratedText{Summary: summary, ForecastDiscussion: []string{discussion}, PrecipitationTiming: timing},
+				Modules:       testTomorrowModules{PrecipTiming: testPrecipitationTimingForGeneratedProseTest()},
+			},
+		},
+		{
+			name:     "hourly",
+			template: "hourly",
+			context: testRenderContext{
+				Report:        testReportContext{Title: "Hourly"},
+				GeneratedText: testGeneratedText{Summary: summary, ForecastDiscussion: discussion, PrecipitationTiming: timing},
+				Modules:       testModules{PrecipTiming: testPrecipitationTimingForGeneratedProseTest()},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			rendered, err := Render(test.template, test.context)
+			if err != nil {
+				t.Fatalf("Render() error = %v", err)
+			}
+			text := string(rendered)
+			for _, want := range []string{
+				"Summary paragraph.\n\n\\## Fabricated Alert\n\\- Fabricated warning\n1\\. Fabricated list\n\\> Fabricated quote",
+				"Discussion paragraph.\n\n\\<script\\>unsafe\\</script\\>\n\\[unsafe\\]\\(javascript:alert\\(1\\)\\)\n\\`\\`\\`code\\`\\`\\`\n\\*\\*emphasis\\*\\*\nindented code ",
+				"Timing paragraph.\n\n\\## Fabricated Timing",
+			} {
+				if !strings.Contains(text, want) {
+					t.Fatalf("rendered template missing escaped prose %q:\n%s", want, text)
+				}
+			}
+			for _, unwanted := range []string{
+				"\n## Fabricated Alert",
+				"\n- Fabricated warning",
+				"\n1. Fabricated list",
+				"\n> Fabricated quote",
+				"<script>unsafe</script>",
+				"[unsafe](javascript:alert(1))",
+				"```code```",
+				"**emphasis**",
+				"\n    indented code",
+				"\n## Fabricated Timing",
+			} {
+				if strings.Contains(text, unwanted) {
+					t.Fatalf("rendered template preserved Markdown structure %q:\n%s", unwanted, text)
+				}
+			}
+		})
+	}
+}
+
+func testPrecipitationTimingForGeneratedProseTest() *testPrecipTiming {
+	return &testPrecipTiming{PrecipitationWindows: []testPrecipWindow{{}}}
+}
+
 func TestUnknownAssetsReturnActionableErrors(t *testing.T) {
 	if _, err := Template("missing"); err == nil || !strings.Contains(err.Error(), `unknown report template "missing"`) {
 		t.Fatalf("Template() error = %v, want unknown template", err)