diff --git a/.github/workflows/build_and_push_docker_image.yml b/.github/workflows/build_and_push_docker_image.yml
index 15fc192fbe..39d226468a 100644
--- a/.github/workflows/build_and_push_docker_image.yml
+++ b/.github/workflows/build_and_push_docker_image.yml
@@ -46,6 +46,10 @@ on:
         required: false
         type: boolean
         default: true
+      fast_rebuild:
+        required: false
+        type: boolean
+        default: false
     outputs:
       build_result:
         description: 'The result of build_and_push job.'
@@ -158,6 +162,7 @@ jobs:
           file: .venv/lib/python3.12/site-packages/dependencies/dockerfiles/${{ inputs.dockerfile }}
           tags: gcr.io/${{ vars.PROJECT_NAME }}/${{ inputs.image_name }}:${{ github.run_id }}
           cache-from: type=gha
+          cache-to: type=gha,mode=max
           outputs: type=image,compression=zstd,force-compression=true
           build-args: |
             DEVICE=${{ inputs.device }}
diff --git a/.github/workflows/ci_pipeline.yml b/.github/workflows/ci_pipeline.yml
index 74b695ae95..0759fcce0b 100644
--- a/.github/workflows/ci_pipeline.yml
+++ b/.github/workflows/ci_pipeline.yml
@@ -30,6 +30,16 @@ on:
         description: 'The result of all_tests_passed and all_notebooks_passed jobs.'
         value: ${{ (jobs.all_tests_passed.result == 'success' && jobs.all_notebooks_passed.result == 'success') && 'success' || 'failure' }}
   workflow_dispatch:
+    inputs:
+      mode:
+        description: 'Test execution mode: build-all (default), test-only (skip package build and run tests), or fast-rebuild'
+        required: false
+        default: 'build-all'
+        type: choice
+        options:
+          - build-all
+          - test-only
+          - fast-rebuild
   schedule:
     # Run the job every 4 hours
     - cron:  '0 */4 * * *'
@@ -142,6 +152,7 @@ jobs:
     # Run if either tests or notebooks need to run; on PRs, gate on code quality + docs passing
     if: |
       always() &&
+      inputs.mode != 'test-only' &&
       (needs.analyze_code_changes.outputs.run_tests == 'true' || needs.analyze_code_changes.outputs.run_notebooks == 'true') &&
       (github.event_name != 'pull_request' || (needs.code_quality_check.result == 'success' && needs.docs_build_check.result == 'success'))
     uses: ./.github/workflows/build_package.yml
@@ -156,7 +167,7 @@ jobs:
     if: |
       always() &&
       needs.analyze_code_changes.outputs.run_notebooks == 'true' &&
-      needs.build_and_upload_maxtext_package.result == 'success'
+      (inputs.mode == 'test-only' || needs.build_and_upload_maxtext_package.result == 'success')
     uses: ./.github/workflows/run_jupyter_notebooks.yml
     strategy:
         fail-fast: false
@@ -165,7 +176,7 @@ jobs:
       device_name: v6e-8
       base_image: maxtext-unit-test-tpu:py312
       cloud_runner: linux-x86-ct6e-180-8tpu
-      maxtext_sha: ${{ needs.build_and_upload_maxtext_package.outputs.maxtext_sha }}
+      maxtext_sha: ${{ needs.build_and_upload_maxtext_package.outputs.maxtext_sha || inputs.maxtext_sha || github.sha }}
     secrets:
       HF_TOKEN: ${{ secrets.HF_TOKEN }}
 
@@ -175,12 +186,12 @@ jobs:
     if: |
       always() &&
       needs.analyze_code_changes.outputs.run_tests == 'true' &&
-      needs.build_and_upload_maxtext_package.result == 'success'
+      (inputs.mode == 'test-only' || needs.build_and_upload_maxtext_package.result == 'success')
     runs-on: ubuntu-latest
     outputs:
       total_workers: ${{ steps.set-params.outputs.total_workers }}
       worker_groups: ${{ steps.set-params.outputs.worker_groups }}
-      maxtext_sha: ${{ needs.build_and_upload_maxtext_package.outputs.maxtext_sha }}
+      maxtext_sha: ${{ needs.build_and_upload_maxtext_package.outputs.maxtext_sha || inputs.maxtext_sha || github.sha }}
     steps:
       - id: set-params
         name: Formalize Test Suite Parameters
diff --git a/.github/workflows/gpu_nightly_images_pipeline.yml b/.github/workflows/gpu_nightly_images_pipeline.yml
index 41d8a9f2aa..47d57d98d0 100644
--- a/.github/workflows/gpu_nightly_images_pipeline.yml
+++ b/.github/workflows/gpu_nightly_images_pipeline.yml
@@ -28,6 +28,15 @@ on:
         required: false
         type: string
         default: ""
+      mode:
+        description: 'Docker test execution mode: build-all (rebuild image and test), test-only (run tests against existing image without rebuild), or fast-rebuild (rebuild code only)'
+        required: false
+        default: 'build-all'
+        type: choice
+        options:
+          - build-all
+          - test-only
+          - fast-rebuild
 
 permissions:
   contents: read
@@ -44,6 +53,7 @@ jobs:
   build_and_push_docker_images:
     name: Build ${{ matrix.name }} Docker Image
     needs: build_maxtext_package
+    if: inputs.mode != 'test-only'
     strategy:
       fail-fast: false
       matrix:
@@ -65,6 +75,7 @@ jobs:
       dockerfile: maxtext_gpu_dependencies.Dockerfile
       maxtext_sha: ${{ needs.build_maxtext_package.outputs.maxtext_sha }}
       include_test_assets: true
+      fast_rebuild: ${{ inputs.mode == 'fast-rebuild' }}
     secrets:
       HF_TOKEN: ${{ secrets.HF_TOKEN }}
 
diff --git a/.github/workflows/tpu_nightly_images_pipeline.yml b/.github/workflows/tpu_nightly_images_pipeline.yml
index 55ee96dafc..8d7f4692ac 100644
--- a/.github/workflows/tpu_nightly_images_pipeline.yml
+++ b/.github/workflows/tpu_nightly_images_pipeline.yml
@@ -28,6 +28,15 @@ on:
         required: false
         type: string
         default: ""
+      mode:
+        description: 'Docker test execution mode: build-all (rebuild image and test), test-only (run tests against existing image without rebuild), or fast-rebuild (rebuild code only)'
+        required: false
+        default: 'build-all'
+        type: choice
+        options:
+          - build-all
+          - test-only
+          - fast-rebuild
 
 permissions:
   contents: read
@@ -44,6 +53,7 @@ jobs:
   build_and_push_docker_images:
     name: Build ${{ matrix.name }} Docker Image
     needs: build_maxtext_package
+    if: inputs.mode != 'test-only'
     strategy:
       fail-fast: false
       matrix:
@@ -70,12 +80,14 @@ jobs:
       maxtext_sha: ${{ needs.build_maxtext_package.outputs.maxtext_sha }}
       include_test_assets: true
       run_tests: false
+      fast_rebuild: ${{ inputs.mode == 'fast-rebuild' }}
     secrets:
       HF_TOKEN: ${{ secrets.HF_TOKEN }}
 
   run_ci_tests:
     name: Run ${{ matrix.name }} CI Tests
     needs: build_and_push_docker_images
+    if: always() && (inputs.mode == 'test-only' || needs.build_and_push_docker_images.result == 'success')
     strategy:
       fail-fast: false
       matrix:
@@ -92,7 +104,7 @@ jobs:
     uses: ./.github/workflows/run_ci_tests.yml
     with:
       image_name: ${{ inputs.image_suffix != '' && format('{0}_{1}', matrix.image_name, inputs.image_suffix) || matrix.image_name }}
-      image_tag: ${{ github.run_id }}
+      image_tag: ${{ inputs.mode == 'test-only' && 'latest' || github.run_id }}
       device: tpu
       workflow: ${{ matrix.workflow }}
 
diff --git a/docs/tutorials/build_maxtext.md b/docs/tutorials/build_maxtext.md
index 4b83bd048a..d458b7fa9e 100644
--- a/docs/tutorials/build_maxtext.md
+++ b/docs/tutorials/build_maxtext.md
@@ -146,6 +146,31 @@ If you get a `command not found: upload_maxtext_docker_image` error, it means yo
 **Note on Permissions:** You will need the [**Artifact Registry Writer**](https://docs.cloud.google.com/artifact-registry/docs/access-control#permissions) role to push Docker images to Artifact Registry. If you don't have this permission, contact your project administrator to grant you this role through "Google Cloud Console -> IAM -> Grant access".
 ````
 
+## Re-Running Tests Without Rebuilding Images
+
+When MaxText tests fail or flake, users often want to re-run their tests with the same dependencies (or even the same code) without waiting to rebuild the Docker image from scratch.
+
+In an ideal setup, users can choose between three execution modes using `run_maxtext_docker_test` (or `bash src/dependencies/scripts/run_docker_test.sh`):
+
+1. **Re-run all steps including building image**:
+   ```bash
+   run_maxtext_docker_test --mode=build-all --command="python3 -m pytest -vv tests/unit/"
+   ```
+2. **Re-run just the tests, using the same image (including same code)**:
+   ```bash
+   run_maxtext_docker_test --mode=test-only --command="python3 -m pytest -vv tests/unit/"
+   ```
+3. **Rebuild the image using the same dependencies, only new code (fast rebuild)**:
+   ```bash
+   run_maxtext_docker_test --mode=fast-rebuild --command="python3 -m pytest -vv tests/unit/"
+   ```
+
+### XPK Workload Option
+
+When running benchmarks or tests on XPK using `benchmarks/maxtext_xpk_runner.py`:
+- Set `reuse_image = True` in `WorkloadConfig` to re-run tests using an existing `--docker-image` without rebuilding or deleting any intermediate images.
+- Set `fast_rebuild = True` in `WorkloadConfig` to fast-rebuild only the runner image over cached dependencies (`docker_upload_runner.sh FAST_REBUILD=true`).
+
 ## Troubleshooting
 
 1. If you see the following error while building or uploading your Docker image, try adding the listed file path to `.dockerignore`. Do not include the `./` prefix in the `.dockerignore` file:
diff --git a/pyproject.toml b/pyproject.toml
index 4b7949c50c..14dda2735e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -48,4 +48,5 @@ install_cuda12_pre_train_extra_deps = "dependencies.scripts.install_pre_train_ex
 install_tpu_post_train_extra_deps = "dependencies.scripts.install_post_train_extra_deps:main"
 build_maxtext_docker_image = "dependencies.scripts.build_maxtext_docker_image:main"
 upload_maxtext_docker_image = "dependencies.scripts.upload_maxtext_docker_image:main"
+run_maxtext_docker_test = "dependencies.scripts.run_docker_test:main"
 run_tutorial = "dependencies.scripts.run_tutorial:main"
diff --git a/src/dependencies/scripts/build_upload_colocated_python_image.sh b/src/dependencies/scripts/build_upload_colocated_python_image.sh
index f208f7b85f..c0aaf9cdab 100644
--- a/src/dependencies/scripts/build_upload_colocated_python_image.sh
+++ b/src/dependencies/scripts/build_upload_colocated_python_image.sh
@@ -125,8 +125,13 @@ FULL_BASE_IMAGE="${BASE_IMAGE_REPO}:${BASE_IMAGE_TAG}"
 echo "  Found latest compatible base image: ${FULL_BASE_IMAGE}"
 
 # --- Step 3: Build the Docker image using --build-arg ---
+CACHE_FLAG="--no-cache"
+if [[ "${FAST_REBUILD:-false}" == "true" || "${NO_CACHE:-true}" == "false" ]]; then
+  CACHE_FLAG=""
+  echo "Fast rebuild enabled: reusing Docker layer cache."
+fi
 echo "$(date): Running docker build with local tag '${LOCAL_IMAGE_NAME}' using ${TMP_DOCKERFILE}..."
-docker build --no-cache \
+docker build ${CACHE_FLAG} \
   -f ${DOCKERFILE_TEMPLATE} \
   --build-arg BASE_IMAGE="${FULL_BASE_IMAGE}" \
   -t "${LOCAL_IMAGE_NAME}" \
@@ -140,7 +145,11 @@ echo "$(date): Pushing '${IMAGE_LOCATION}'..."
 docker push "${IMAGE_LOCATION}"
 
 # --- Step 5: Cleanup ---
-echo "$(date): Cleaning up local tag '${LOCAL_IMAGE_NAME}'..."
-docker image rm "${LOCAL_IMAGE_NAME}"
+if [[ "${CLEANUP_IMAGE:-true}" == "true" ]]; then
+  echo "$(date): Cleaning up local tag '${LOCAL_IMAGE_NAME}'..."
+  docker image rm "${LOCAL_IMAGE_NAME}"
+else
+  echo "$(date): Preserving local tag '${LOCAL_IMAGE_NAME}' (CLEANUP_IMAGE=false)..."
+fi
 
 echo "$(date): Build and push complete for ${IMAGE_LOCATION}"
diff --git a/src/dependencies/scripts/docker_upload_runner.sh b/src/dependencies/scripts/docker_upload_runner.sh
index f7b98a4581..800ea7bf9a 100644
--- a/src/dependencies/scripts/docker_upload_runner.sh
+++ b/src/dependencies/scripts/docker_upload_runner.sh
@@ -116,7 +116,13 @@ if ! docker image inspect "${LOCAL_IMAGE_NAME}" &> /dev/null; then
   exit 1
 fi
 
-docker build --no-cache --build-arg BASEIMAGE=${LOCAL_IMAGE_NAME} \
+CACHE_FLAG="--no-cache"
+if [[ "${FAST_REBUILD:-false}" == "true" || "${NO_CACHE:-true}" == "false" ]]; then
+  CACHE_FLAG=""
+  echo "Fast rebuild enabled: reusing Docker layer cache for runner image build."
+fi
+
+docker build ${CACHE_FLAG} --build-arg BASEIMAGE=${LOCAL_IMAGE_NAME} \
              --build-arg PACKAGE_DIR=${PACKAGE_DIR} \
              -f "$PACKAGE_DIR"'/dependencies/dockerfiles/maxtext_runner.Dockerfile' \
              -t ${LOCAL_IMAGE_NAME_RUNNER} .
diff --git a/src/dependencies/scripts/run_docker_test.py b/src/dependencies/scripts/run_docker_test.py
new file mode 100644
index 0000000000..130c3309bd
--- /dev/null
+++ b/src/dependencies/scripts/run_docker_test.py
@@ -0,0 +1,36 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Wrapper to run run_docker_test.sh from pip install or module execution."""
+
+import os
+import sys
+
+
+def main():
+  current_dir = os.path.dirname(os.path.abspath(__file__))
+  repo_root = os.path.abspath(os.path.join(current_dir, "..", ".."))
+  # Use relative path for Docker
+  os.environ["PACKAGE_DIR"] = os.path.relpath(repo_root, os.getcwd())
+
+  script_path = os.path.join(current_dir, "run_docker_test.sh")
+  if not os.path.exists(script_path):
+    raise FileNotFoundError(f"Script not found at {script_path}")
+
+  cmd = ["bash", script_path] + sys.argv[1:]
+  os.execvp("bash", cmd)
+
+
+if __name__ == "__main__":
+  main()
diff --git a/src/dependencies/scripts/run_docker_test.sh b/src/dependencies/scripts/run_docker_test.sh
new file mode 100755
index 0000000000..5e338eb66d
--- /dev/null
+++ b/src/dependencies/scripts/run_docker_test.sh
@@ -0,0 +1,235 @@
+#!/bin/bash
+# Copyright 2023–2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This script runs MaxText unit, integration, or end-to-end tests in Docker containers
+# while allowing users to choose whether to build all images, perform a fast rebuild
+# of only code layers, or re-run tests using an existing image.
+#
+# Supported modes:
+#   1. build-all    : Re-run all steps including building the base dependency image and runner image.
+#   2. test-only    : Re-run just the tests using the existing image (no build, fast re-run).
+#   3. fast-rebuild : Rebuild the runner image using cached dependencies, updating only code.
+
+set -e
+
+# Default parameter values
+PACKAGE_DIR="${PACKAGE_DIR:-src}"
+MODE="${MODE:-build-all}"
+COMMAND="${COMMAND:-python3 -m pytest -vv tests/unit/}"
+BASE_IMAGE="${BASE_IMAGE:-maxtext_base_image}"
+IMAGE_NAME="${IMAGE_NAME:-maxtext_base_image__runner}"
+DEVICE="${DEVICE:-tpu}"
+BUILD_MODE="${BUILD_MODE:-stable}"
+CLEANUP_IMAGE="${CLEANUP_IMAGE:-false}"
+DOCKER_RUN_FLAGS="${DOCKER_RUN_FLAGS:-}"
+
+# Parse command line flags and key=value arguments
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    -m|--mode)
+      MODE="$2"
+      shift 2
+      ;;
+    --mode=*)
+      MODE="${1#*=}"
+      shift 1
+      ;;
+    -c|--command)
+      COMMAND="$2"
+      shift 2
+      ;;
+    --command=*)
+      COMMAND="${1#*=}"
+      shift 1
+      ;;
+    -i|--image)
+      IMAGE_NAME="$2"
+      shift 2
+      ;;
+    --image=*)
+      IMAGE_NAME="${1#*=}"
+      shift 1
+      ;;
+    --base-image=*)
+      BASE_IMAGE="${1#*=}"
+      shift 1
+      ;;
+    --cleanup)
+      CLEANUP_IMAGE="true"
+      shift 1
+      ;;
+    --no-cleanup)
+      CLEANUP_IMAGE="false"
+      shift 1
+      ;;
+    --cleanup=*)
+      CLEANUP_IMAGE="${1#*=}"
+      shift 1
+      ;;
+    *=*)
+      IFS='=' read -r KEY VALUE <<< "$1"
+      export "${KEY}"="${VALUE}"
+      shift 1
+      ;;
+    -h|--help)
+      echo "Usage: $0 [OPTIONS] [KEY=VALUE...]"
+      echo ""
+      echo "Options:"
+      echo "  -m, --mode <mode>        Execution mode:"
+      echo "                             build-all    : Build dependency image + runner image + run tests"
+      echo "                             test-only    : Run tests using existing image (no rebuild)"
+      echo "                             fast-rebuild : Rebuild only runner code layer + run tests"
+      echo "  -c, --command <cmd>      Command to execute inside Docker container"
+      echo "                           (default: 'python3 -m pytest -vv tests/unit/')"
+      echo "  -i, --image <name>       Runner Docker image name (default: maxtext_base_image__runner)"
+      echo "      --base-image <name>  Base dependency Docker image name (default: maxtext_base_image)"
+      echo "      --cleanup=<bool>     Remove image after test run (default: false)"
+      echo ""
+      exit 0
+      ;;
+    *)
+      echo "ERROR: Unknown argument: $1" >&2
+      exit 1
+      ;;
+  esac
+done
+
+# Normalize mode string
+case "${MODE}" in
+  build-all|rebuild-all|all|1)
+    MODE="build-all"
+    ;;
+  test-only|reuse-image|no-build|2)
+    MODE="test-only"
+    ;;
+  fast-rebuild|rebuild-code|code-only|3)
+    MODE="fast-rebuild"
+    ;;
+  *)
+    echo "ERROR: Invalid mode '${MODE}'. Supported modes: build-all, test-only, fast-rebuild." >&2
+    exit 1
+    ;;
+esac
+
+echo "=========================================================="
+echo "MaxText Docker Test Runner"
+echo "=========================================================="
+echo "Mode           : ${MODE}"
+echo "Runner Image   : ${IMAGE_NAME}"
+echo "Base Image     : ${BASE_IMAGE}"
+echo "Test Command   : ${COMMAND}"
+echo "Cleanup Image  : ${CLEANUP_IMAGE}"
+echo "=========================================================="
+
+# Check for Docker daemon access
+if ! docker info > /dev/null 2>&1; then
+  echo "ERROR: Permission denied while trying to connect to the Docker daemon." >&2
+  echo "Please check your Docker permissions (sudo, docker group, etc.)." >&2
+  exit 1
+fi
+
+build_base_image() {
+  echo "----------------------------------------------------------"
+  echo "Step 1: Building base dependency image '${BASE_IMAGE}'..."
+  echo "----------------------------------------------------------"
+  if [[ -f "${PACKAGE_DIR}/dependencies/scripts/docker_build_dependency_image.sh" ]]; then
+    bash "${PACKAGE_DIR}/dependencies/scripts/docker_build_dependency_image.sh" \
+      DEVICE="${DEVICE}" MODE="${BUILD_MODE}" LOCAL_IMAGE_NAME="${BASE_IMAGE}"
+  else
+    echo "ERROR: Base image build script not found under ${PACKAGE_DIR}/dependencies/scripts/" >&2
+    exit 1
+  fi
+}
+
+build_runner_image() {
+  local use_cache="$1"
+  echo "----------------------------------------------------------"
+  echo "Step 2: Building runner image '${IMAGE_NAME}' from '${BASE_IMAGE}'..."
+  echo "        Cache enabled: ${use_cache}"
+  echo "----------------------------------------------------------"
+  if ! docker image inspect "${BASE_IMAGE}" >/dev/null 2>&1; then
+    echo "ERROR: Base dependency image '${BASE_IMAGE}' not found locally." >&2
+    echo "       Please run with '--mode=build-all' first to build the base dependencies." >&2
+    exit 1
+  fi
+
+  local cache_args=()
+  if [[ "${use_cache}" == "false" ]]; then
+    cache_args+=("--no-cache")
+  fi
+
+  docker build "${cache_args[@]}" \
+    --build-arg BASEIMAGE="${BASE_IMAGE}" \
+    --build-arg PACKAGE_DIR="${PACKAGE_DIR}" \
+    -f "${PACKAGE_DIR}/dependencies/dockerfiles/maxtext_runner.Dockerfile" \
+    -t "${IMAGE_NAME}" .
+}
+
+case "${MODE}" in
+  build-all)
+    build_base_image
+    build_runner_image "false"
+    ;;
+  fast-rebuild)
+    build_runner_image "true"
+    ;;
+  test-only)
+    echo "----------------------------------------------------------"
+    echo "Skipping image build. Verifying runner image '${IMAGE_NAME}' exists..."
+    echo "----------------------------------------------------------"
+    if ! docker image inspect "${IMAGE_NAME}" >/dev/null 2>&1; then
+      echo "ERROR: Runner image '${IMAGE_NAME}' not found locally." >&2
+      echo "       Cannot re-run tests without an existing image." >&2
+      echo "       Use '--mode=build-all' or '--mode=fast-rebuild' to create the image first." >&2
+      exit 1
+    fi
+    ;;
+esac
+
+echo "----------------------------------------------------------"
+echo "Step 3: Running test command inside container '${IMAGE_NAME}'..."
+echo "----------------------------------------------------------"
+
+set +e
+docker run --rm -it --network host --privileged \
+  -e MAXTEXT_REPO_ROOT=/deps \
+  -e MAXTEXT_PKG_DIR=/deps/src/maxtext \
+  -v "$(pwd):/deps" \
+  ${DOCKER_RUN_FLAGS} \
+  "${IMAGE_NAME}" \
+  bash -c "${COMMAND}"
+TEST_EXIT_CODE=$?
+set -e
+
+echo "----------------------------------------------------------"
+if [[ "${TEST_EXIT_CODE}" -eq 0 ]]; then
+  echo "TEST RESULT: SUCCESS (Exit code 0)"
+else
+  echo "TEST RESULT: FAILURE (Exit code ${TEST_EXIT_CODE})"
+fi
+
+if [[ "${CLEANUP_IMAGE}" == "true" ]]; then
+  echo "Cleaning up Docker image '${IMAGE_NAME}' as requested..."
+  docker image rm "${IMAGE_NAME}" 2>/dev/null || true
+else
+  echo "----------------------------------------------------------"
+  echo "NOTICE: Docker image '${IMAGE_NAME}' has been preserved."
+  echo "  - To re-run tests without rebuilding image  : bash $0 --mode=test-only"
+  echo "  - To rebuild only code layers (fast rebuild): bash $0 --mode=fast-rebuild"
+  echo "  - To rebuild all dependencies from scratch    : bash $0 --mode=build-all"
+  echo "----------------------------------------------------------"
+fi
+
+exit "${TEST_EXIT_CODE}"
diff --git a/tests/unit/run_docker_test_test.py b/tests/unit/run_docker_test_test.py
new file mode 100644
index 0000000000..de10688d62
--- /dev/null
+++ b/tests/unit/run_docker_test_test.py
@@ -0,0 +1,93 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Unit tests for MaxText Docker testing scripts and XPK reuse-image / fast-rebuild options."""
+
+import os
+import subprocess
+import unittest
+from unittest import mock
+
+import pytest
+
+@pytest.mark.cpu_only
+class RunDockerTestTest(unittest.TestCase):
+  """Tests for run_docker_test.sh / run_docker_test.py CLI options."""
+
+  def test_run_docker_test_help(self):
+    current_dir = os.path.dirname(os.path.abspath(__file__))
+    repo_root = os.path.abspath(os.path.join(current_dir, "..", ".."))
+    script_path = os.path.join(repo_root, "src", "dependencies", "scripts", "run_docker_test.sh")
+
+    result = subprocess.run(
+        ["bash", script_path, "--help"],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        text=True,
+        check=False,
+    )
+    self.assertEqual(result.returncode, 0)
+    self.assertIn("build-all", result.stdout)
+    self.assertIn("test-only", result.stdout)
+    self.assertIn("fast-rebuild", result.stdout)
+
+  def test_run_docker_test_invalid_mode(self):
+    current_dir = os.path.dirname(os.path.abspath(__file__))
+    repo_root = os.path.abspath(os.path.join(current_dir, "..", ".."))
+    script_path = os.path.join(repo_root, "src", "dependencies", "scripts", "run_docker_test.sh")
+
+    result = subprocess.run(
+        ["bash", script_path, "--mode=invalid_mode"],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        text=True,
+        check=False,
+    )
+    self.assertNotEqual(result.returncode, 0)
+    self.assertIn("Invalid mode", result.stderr)
+
+  def test_run_docker_test_fast_rebuild_mode(self):
+    current_dir = os.path.dirname(os.path.abspath(__file__))
+    repo_root = os.path.abspath(os.path.join(current_dir, "..", ".."))
+    script_path = os.path.join(repo_root, "src", "dependencies", "scripts", "run_docker_test.sh")
+
+    result = subprocess.run(
+        ["bash", script_path, "--mode=fast-rebuild", "--base-image=non_existent_base_img_999"],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        text=True,
+        check=False,
+    )
+    self.assertIn("Mode           : fast-rebuild", result.stdout)
+    self.assertIn("not found locally", result.stderr)
+
+  def test_run_docker_test_test_only_mode(self):
+    current_dir = os.path.dirname(os.path.abspath(__file__))
+    repo_root = os.path.abspath(os.path.join(current_dir, "..", ".."))
+    script_path = os.path.join(repo_root, "src", "dependencies", "scripts", "run_docker_test.sh")
+
+    result = subprocess.run(
+        ["bash", script_path, "--mode=test-only", "--image=non_existent_test_img_456"],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        text=True,
+        check=False,
+    )
+    self.assertIn("Mode           : test-only", result.stdout)
+    self.assertIn("Skipping image build.", result.stdout)
+    self.assertIn("not found locally", result.stderr)
+
+
+if __name__ == "__main__":
+  unittest.main()