diff --git a/CONTRIBUTING.rst b/CONTRIBUTING.rst
index 07136dcad..da33b0cff 100644
--- a/CONTRIBUTING.rst
+++ b/CONTRIBUTING.rst
@@ -219,12 +219,10 @@ Or you can run them on a fish, without involving cmake::
 
   cargo build
   cargo test # for the unit tests
-  tests/test_driver.py --cachedir=/tmp target/debug # for the script and interactive tests
+  tests/test_driver.py target/debug # for the script and interactive tests
 
 Here, the first argument to test_driver.py refers to a directory with ``fish``, ``fish_indent`` and ``fish_key_reader`` in it.
 In this example we're in the root of the git repo and have run ``cargo build`` without ``--release``, so it's a debug build.
-The ``--cachedir /tmp`` argument means it will keep the fish_test_helper binary in /tmp instead of recompiling it for every test.
-This saves some time, but isn't strictly necessary.
 
 Git hooks
 ---------
diff --git a/cmake/Tests.cmake b/cmake/Tests.cmake
index 8bc525039..849a6c7e4 100644
--- a/cmake/Tests.cmake
+++ b/cmake/Tests.cmake
@@ -63,7 +63,7 @@ foreach(CHECK ${FISH_CHECKS})
   get_filename_component(CHECK_NAME ${CHECK} NAME)
   get_filename_component(CHECK ${CHECK} NAME_WE)
   add_test(NAME ${CHECK_NAME}
-    COMMAND ${CMAKE_SOURCE_DIR}/tests/test_driver.py --cachedir=${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_BINARY_DIR}
+    COMMAND ${CMAKE_SOURCE_DIR}/tests/test_driver.py ${CMAKE_CURRENT_BINARY_DIR}
                 checks/${CHECK}.fish
     WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}/tests
   )
@@ -76,7 +76,7 @@ FILE(GLOB PEXPECTS CONFIGURE_DEPENDS ${CMAKE_SOURCE_DIR}/tests/pexpects/*.py)
 foreach(PEXPECT ${PEXPECTS})
   get_filename_component(PEXPECT ${PEXPECT} NAME)
   add_test(NAME ${PEXPECT}
-    COMMAND ${CMAKE_SOURCE_DIR}/tests/test_driver.py --cachedir=${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_BINARY_DIR}
+    COMMAND ${CMAKE_SOURCE_DIR}/tests/test_driver.py ${CMAKE_CURRENT_BINARY_DIR}
                 pexpects/${PEXPECT}
     WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}/tests
   )
diff --git a/tests/test_driver.py b/tests/test_driver.py
index f99140820..a22103529 100755
--- a/tests/test_driver.py
+++ b/tests/test_driver.py
@@ -80,25 +80,15 @@ def makeenv(script_path: Path, home: Path):
     )
 
 
-def compile_test_helper(
-    cachedir: Optional[str], source_path: Path, binary_path: Path
-) -> None:
-    # Compile fish_test_helper if necessary.
-    # If we're run multiple times, allow keeping this around to save time.
-    if cachedir:
-        thp = Path(cachedir) / "fish_test_helper"
-        if not os.path.exists(thp):
-            subprocess.run(["cc", source_path, "-o", thp])
-        shutil.copy(thp, binary_path)
-    else:
-        subprocess.run(
-            [
-                "cc",
-                source_path,
-                "-o",
-                binary_path,
-            ]
-        )
+def compile_test_helper(source_path: Path, binary_path: Path) -> None:
+    subprocess.run(
+        [
+            "cc",
+            source_path,
+            "-o",
+            binary_path,
+        ]
+    )
 
 
 def main():
@@ -111,14 +101,6 @@ def main():
     argparser = argparse.ArgumentParser(
         description="test_driver: Run fish's test suite"
     )
-    argparser.add_argument(
-        "-f",
-        "--cachedir",
-        type=str,
-        help="Path to keep outputs to speed up the next run",
-        action="store",
-        default=None,
-    )
     argparser.add_argument("fish", nargs=1, help="Fish to test")
     argparser.add_argument("file", nargs="*", help="Tests to run")
     args = argparser.parse_args()
@@ -176,7 +158,6 @@ def main():
         tmp_root = Path(tmp_root)
 
         compile_test_helper(
-            args.cachedir,
             script_path / "fish_test_helper.c",
             tmp_root / "fish_test_helper",
         )