diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index 30730141c7b..7d194f7e77e 100644
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -104,10 +104,14 @@ jobs:
         CUPY_CACHE_DIR: "${{ env.CACHE_DIR }}\\.cupy"
         GPU: 1
       run: |
-        echo "test"
-        ni -force -ItemType File -Path "$env:CUPY_CACHE_DIR\\abc"
+        #echo "test"
+        #ni -force -ItemType File -Path "$env:CUPY_CACHE_DIR\\abc"
+        # The next step requires this environment variable to be visible
         echo "CUPY_CACHE_DIR=$env:CUPY_CACHE_DIR" >> $env:GITHUB_ENV
-        #.pfnci\windows\run.bat 12.0 3.10 test
+        # FIXME: get the version strings from a test matrix
+        .pfnci\windows\GHA-test.ps1 -stage setup -python 3.10 -cuda 12.6
+        .pfnci\windows\GHA-test.ps1 -stage build
+        .pfnci\windows\GHA-test.ps1 -stage test
 
     - name: Prepare cache
       id: prepare-cache
diff --git a/.pfnci/windows/GHA-test.ps1 b/.pfnci/windows/GHA-test.ps1
new file mode 100644
index 00000000000..2d203f2a69d
--- /dev/null
+++ b/.pfnci/windows/GHA-test.ps1
@@ -0,0 +1,94 @@
+Param(
+    [Parameter(Mandatory=$true)]
+    [String]$stage,
+    [Parameter(Mandatory=$false)]
+    [String]$python,
+    [Parameter(Mandatory=$false)]
+    [String]$cuda
+)
+
+$ErrorActionPreference = "Stop"
+. "$PSScriptRoot\_error_handler.ps1"
+
+. "$PSScriptRoot\_flexci.ps1"
+
+
+function Main {
+    # Setup environment
+    if ($stage -eq "setup") {
+        echo "Using CUDA $cuda and Python $python"
+        ActivateCUDA $cuda
+        if ($cuda -eq "10.2") {
+            ActivateCuDNN "8.6" $cuda
+        } else {
+            ActivateCuDNN "8.8" $cuda
+        }
+        ActivateNVTX1
+        ActivatePython $python
+        echo "Setting up test environment"
+        RunOrDie python -V
+        RunOrDie python -m pip install -U pip setuptools wheel
+        RunOrDie python -m pip freeze
+
+        return
+    }
+    elseif ($stage -eq "build") {
+        # Setup build environment variables
+        $Env:CUPY_NUM_BUILD_JOBS = "16"
+        $Env:CUPY_NVCC_GENERATE_CODE = "current"
+        echo "Environment:"
+        RunOrDie cmd.exe /C set
+
+        echo "Building..."
+        $build_retval = 0
+        RunOrDie python -m pip install -U "numpy" "scipy==1.12.*"
+        python -m pip install ".[all,test]" -v
+        if (-not $?) {
+            $build_retval = $LastExitCode
+        }
+
+        if ($build_retval -ne 0) {
+            throw "Build failed with status $build_retval"
+        }
+
+        return
+    }
+    elseif ($stage -eq "test") {
+        $pytest_opts = "-m", '"not slow"'
+    }
+    elseif ($stage -eq "slow") {
+        $pytest_opts = "-m", "slow"
+    }
+    else {
+        throw "Unsupported stage: $stage"
+    }
+
+    $Env:CUPY_TEST_GPU_LIMIT = $Env:GPU
+    $Env:CUPY_DUMP_CUDA_SOURCE_ON_ERROR = "1"
+
+    # # TODO: update this function?
+    # $is_pull_request = IsPullRequestTest
+    # if (-Not $is_pull_request) {
+    #     $Env:CUPY_TEST_FULL_COMBINATION = "1"
+    # }
+
+    # # TODO: do we still need zlib these days?
+    # # Install dependency for cuDNN 8.3+
+    # echo ">> Installing zlib"
+    # InstallZLIB
+
+    pushd tests
+    echo "CuPy Configuration:"
+    RunOrDie python -c "import cupy; print(cupy); cupy.show_config()"
+    echo "Running test..."
+    $pytest_tests = "cupy_tests/core_tests/test*.py"  # TODO: remove me
+    # TODO: pass timeout as a function argument?
+    $test_retval = RunWithTimeout -timeout 18000 -- python -m pytest -rfEX @pytest_opts @pytest_tests
+    popd
+
+    if ($test_retval -ne 0) {
+        throw "Test failed with status $test_retval"
+    }
+}
+
+Main
diff --git a/.pfnci/windows/_error_handler.ps1 b/.pfnci/windows/_error_handler.ps1
index 5750a59e014..79f895d1e1d 100644
--- a/.pfnci/windows/_error_handler.ps1
+++ b/.pfnci/windows/_error_handler.ps1
@@ -18,14 +18,18 @@ function RunWithTimeout {
     param(
         [Parameter(Mandatory=$true)]
         [int]$timeout,
-        [Parameter(Mandatory=$true)]
+        [Parameter(Mandatory=$false)]
         [string]$output,
         [Parameter(Mandatory=$true)]
         [string]$command,
         [Parameter(Mandatory=$true, ValueFromRemainingArguments=$true)]
         [string[]]$params
     )
-    $process = Start-Process -PassThru -NoNewWindow -RedirectStandardOutput $output -FilePath $command -ArgumentList $params
+    if ($PSBoundParameters.ContainsKey('output')) {
+        $process = Start-Process -PassThru -NoNewWindow -RedirectStandardOutput $output -FilePath $command -ArgumentList $params
+    } else {
+        $process = Start-Process -PassThru -NoNewWindow -FilePath $command -ArgumentList $params
+    }
     try {
         $process | Wait-Process -Timeout $timeout
     } catch [TimeoutException] {