1 files changed, 51 insertions, 0 deletions
diff --git a/comments_test.go b/comments_test.go
new file mode 100644
index 0000000..a6c5a47
--- /dev/null
+++ b/comments_test.go
@@ -0,0 +1,51 @@
+package devianter
+
+import "testing"
+
+// Regression: flattenComment's shape check used to read m[0] and m[len(m)-1]
+// without a length check, so a comment with an empty markup body panicked with
+// index out of range and killed the caller's process.
+func TestFlattenCommentEmptyMarkup(t *testing.T) {
+	if got := flattenComment(""); got != "" {
+		t.Errorf("want an empty comment for empty markup, got %q", got)
+	}
+}
+
+func TestFlattenComment(t *testing.T) {
+	// A newer, Draft.js-encoded body is flattened to its text.
+	draft := `{"blocks":[{"text":"hello there"}]}`
+	if got := flattenComment(draft); got != "hello there" {
+		t.Errorf("want the Draft.js block text, got %q", got)
+	}
+
+	// An older, plain-HTML body passes through untouched.
+	html := "<b>hello</b> there"
+	if got := flattenComment(html); got != html {
+		t.Errorf("want plain HTML passed through, got %q", got)
+	}
+
+	// Regression: the block loop used to assign rather than accumulate, so every
+	// block but the last was silently dropped and a multi-paragraph comment came
+	// back as its closing line only.
+	multi := `{"blocks":[{"text":"first"},{"text":"second"},{"text":"third"}]}`
+	if got, want := flattenComment(multi), "first\nsecond\nthird"; got != want {
+		t.Errorf("want every block, one per line:\n got %q\nwant %q", got, want)
+	}
+
+	// An empty block is a blank line in the comment, not something to skip.
+	blank := `{"blocks":[{"text":"first"},{"text":""},{"text":"third"}]}`
+	if got, want := flattenComment(blank), "first\n\nthird"; got != want {
+		t.Errorf("want an empty block preserved as a blank line:\n got %q\nwant %q", got, want)
+	}
+
+	// Brace-shaped markup that isn't a Draft.js document falls back to itself
+	// rather than to an empty string.
+	if got := flattenComment("{}"); got != "{}" {
+		t.Errorf("want the original markup when there are no blocks, got %q", got)
+	}
+
+	// A single brace satisfies neither end of the shape check.
+	if got := flattenComment("{"); got != "{" {
+		t.Errorf("want a lone brace passed through, got %q", got)
+	}
+}