Initial patterm project

internal/app/screen_renderer_test.go

@@ -0,0 +1,33 @@
+package app
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/harrybrwn/patterm/internal/vt"
+)
+
+func TestRenderScreenSnapshotClipsRowsToViewport(t *testing.T) {
+	layout := newTerminalLayout(20, 5)
+	got := string(renderScreenSnapshot("abcdefghijklmnopqrstuvwxy\nsecond", vt.CursorState{}, layout))
+	if strings.Contains(got, "uvwxy") {
+		t.Fatalf("line leaked past viewport width: %q", got)
+	}
+	if !strings.Contains(got, "\x1b[2;1Habcdefghijklmnopqrst") {
+		t.Fatalf("first row not drawn at viewport top: %q", got)
+	}
+	if !strings.Contains(got, "\x1b[3;1Hsecond              ") {
+		t.Fatalf("second row not padded in viewport: %q", got)
+	}
+	if !strings.Contains(got, "\x1b[4;1H                    ") {
+		t.Fatalf("blank viewport row not cleared: %q", got)
+	}
+}
+
+func TestRenderScreenSnapshotPlacesCursorInsideViewport(t *testing.T) {
+	layout := newTerminalLayout(20, 5)
+	got := string(renderScreenSnapshot("abc", vt.CursorState{Col: 2, Row: 1, Visible: true}, layout))
+	if !strings.HasSuffix(got, "\x1b[?25h\x1b[3;3H") {
+		t.Fatalf("cursor not placed inside viewport: %q", got)
+	}
+}