diff --git a/tests/integration/__tests__/debug-api.js b/tests/integration/__tests__/debug-api.js
index af38a2937..d2145a7f8 100644
--- a/tests/integration/__tests__/debug-api.js
+++ b/tests/integration/__tests__/debug-api.js
@@ -72,18 +72,6 @@ describe("API", () => {
       await formatDoc(fill(["foo", hardline, "bar", literalline, "baz"])),
     ).toBe('fill(["foo", hardline, "bar", literalline, "baz"])');
 
-    /*
-    This is not really `cleanDoc` from `src/document/utils.js`
-    But if we pass array to it, it will flat array
-    */
-    const cleanDoc = (parts) => parts.flat();
-    expect(
-      await formatDoc(
-        // The argument of fill must not be passed to cleanDoc because it's not a doc
-        fill(cleanDoc(["foo", literalline, "bar"])), // invalid fill
-      ),
-    ).toBe('fill(["foo", literallineWithoutBreakParent, breakParent, "bar"])');
-
     expect(
       await formatDoc(indentIfBreak(group(["1", line, "2"]), { groupId: "Q" })),
     ).toBe('indentIfBreak(group(["1", line, "2"]), { groupId: "Q" })');
diff --git a/tests/integration/__tests__/doc-builders.js b/tests/integration/__tests__/doc-builders.js
index b554f90ad..2d42d26c8 100644
--- a/tests/integration/__tests__/doc-builders.js
+++ b/tests/integration/__tests__/doc-builders.js
@@ -5,6 +5,7 @@ const {
   literalline,
   group,
   fill,
+  line,
   lineSuffix,
   breakParent,
   ifBreak,
@@ -33,7 +34,7 @@ describe("doc builders", () => {
         expandedStates: undefined,
       },
     ],
-    ["fill", fill(["1", "2"]), { type: "fill", parts: ["1", "2"] }],
+    ["fill", fill(["1", line, "2"]), { type: "fill", parts: ["1", line, "2"] }],
     [
       "line-suffix",
       lineSuffix(["1"]),
diff --git a/tests/integration/__tests__/doc-utils-clean-doc.js b/tests/integration/__tests__/doc-utils-clean-doc.js
index 9372b6b12..699832780 100644
--- a/tests/integration/__tests__/doc-utils-clean-doc.js
+++ b/tests/integration/__tests__/doc-utils-clean-doc.js
@@ -4,6 +4,7 @@ import {
   group,
   ifBreak,
   indent,
+  line,
   lineSuffix,
 } from "../../../src/document/builders.js";
 import { cleanDoc } from "../../../src/document/utils.js";
@@ -12,8 +13,8 @@ describe("cleanDoc", () => {
   test.each([
     [
       "fill",
-      [fill(["", ""]), fill([]), fill(["1"]), fill(["2", "3"])],
-      [fill(["1"]), fill(["2", "3"])],
+      [fill([""]), fill([]), fill(["1"]), fill(["2", line, "3"])],
+      [fill(["1"]), fill(["2", line, "3"])],
     ],
     ["nested group", group(group("_")), group("_")],
     [