diff --git a/test/text-passthrough.test.ts b/test/text-passthrough.test.ts
new file mode 100644
index 0000000..0cb84ad
--- /dev/null
+++ b/test/text-passthrough.test.ts
@@ -0,0 +1,45 @@
+import { beforeEach, describe, expect, it } from "./suite.ts";
+import { createTerm, type Term } from "../term.ts";
+import { close, grow, open, text } from "../ops.ts";
+
+const decode = (b: Uint8Array) => new TextDecoder().decode(b);
+const ESC = String.fromCharCode(0x1b);
+
+describe("text escape passthrough", () => {
+  let term: Term;
+  beforeEach(async () => {
+    term = await createTerm({ width: 40, height: 3 });
+  });
+
+  it("preserves embedded SGR color escape bytes verbatim", () => {
+    let input = ESC + "[32mgreen" + ESC + "[0m normal";
+    let ansi = decode(
+      term.render([
+        open("root", {
+          layout: { width: grow(), height: grow(), direction: "ttb" },
+        }),
+        text(input, { passthrough: true } as never),
+        close(),
+      ]).output,
+    );
+    // the raw input SGR open byte must survive into the output
+    expect(ansi).toContain(ESC + "[32m");
+    // and the reset byte too
+    expect(ansi).toContain(ESC + "[0m normal");
+  });
+
+  it("does not substitute U+FFFD for embedded ESC bytes", () => {
+    let input = ESC + "[32mx" + ESC + "[0m";
+    let ansi = decode(
+      term.render([
+        open("root", {
+          layout: { width: grow(), height: grow(), direction: "ttb" },
+        }),
+        text(input, { passthrough: true } as never),
+        close(),
+      ]).output,
+    );
+    // no replacement glyph should appear where the ESC bytes were stripped
+    expect(ansi.includes("�")).toBe(false);
+  });
+});