checklist: Add test to avoid filtering separators

There was a bug in the checklist substitution which caused issue content
following a horizontal separator to be discarded rather than posted into
the target issue. Add a test to catch this case.

Signed-off-by: Joe Stringer <[email protected]>

cmd/checklist/template_test.go

@@ -6,6 +6,7 @@ package checklist
 import (
 	"os"
 	"path/filepath"
+	"regexp"
 	"testing"
 
 	"github.com/go-quicktest/qt"
@@ -104,3 +105,37 @@ func Test_prepareChecklist(t *testing.T) {
 		})
 	}
 }
+
+func Test_templateToRequest(t *testing.T) {
+	cfg := ChecklistConfig{
+		TargetVer: "v1.10.0-pre.0",
+	}
+	testdataPath := filepath.Join("..", "..", "testdata", "checklist")
+
+	paths, err := filepath.Glob(filepath.Join(testdataPath, "*.input"))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for _, path := range paths {
+		_, filename := filepath.Split(path)
+		testname := filename[:len(filename)-len(filepath.Ext(path))]
+
+		t.Run(testname, func(t *testing.T) {
+			source, err := os.ReadFile(path)
+			qt.Assert(t, qt.IsNil(err), qt.Commentf("failed to read input template: %w", err))
+
+			barRe := regexp.MustCompile(`---`)
+			expBarCount := len(barRe.FindAll(source, -1)) - 2 // Exclude the metadata section at the top
+
+			cl, err := prepareChecklist(source, cfg)
+			qt.Assert(t, qt.IsNil(err), qt.Commentf("failed to render checklist: %w", err))
+
+			req, err := templateToRequest(cl)
+			qt.Assert(t, qt.IsNil(err), qt.Commentf("failed to translate checklist into GitHub request: %w", err))
+
+			barCount2 := barRe.FindAllString(*req.Body, -1)
+			qt.Assert(t, qt.Equals(len(barCount2), expBarCount), qt.Commentf("template unexpectedly trimmed valid horizontal separators"))
+		})
+	}
+}