diff --git a/.github/workflows/test-windows.yml b/.github/workflows/test-windows.yml
index 96e4b1d5fd8..3c574668334 100644
--- a/.github/workflows/test-windows.yml
+++ b/.github/workflows/test-windows.yml
@@ -47,6 +47,12 @@ jobs:
         repository: python-pillow/pillow-depends
         path: winbuild\depends
 
+    - name: Checkout extra test images
+      uses: actions/checkout@v4
+      with:
+        repository: python-pillow/test-images
+        path: Tests\test-images
+
     # sets env: pythonLocation
     - name: Set up Python
       uses: actions/setup-python@v5
@@ -59,9 +65,29 @@ jobs:
     - name: Print build system information
       run: python3 .github/workflows/system-info.py
 
+    - name: Install Python dependencies
+      run: >
+        python3 -m pip install
+        coverage>=7.4.2
+        defusedxml
+        olefile
+        pyroma
+        pytest
+        pytest-cov
+        pytest-timeout
+
     - name: Install dependencies
       id: install
       run: |
+        choco install nasm --no-progress
+        echo "C:\Program Files\NASM" >> $env:GITHUB_PATH
+
+        choco install ghostscript --version=10.3.0 --no-progress
+        echo "C:\Program Files\gs\gs10.00.0\bin" >> $env:GITHUB_PATH
+
+        # Install extra test images
+        xcopy /S /Y Tests\test-images\* Tests\images
+
         # make cache key depend on VS version
         & "C:\Program Files (x86)\Microsoft Visual Studio\Installer\vswhere.exe" `
           | find """catalog_buildVersion""" `
@@ -90,9 +116,54 @@ jobs:
       if: steps.build-cache.outputs.cache-hit != 'true'
       run: "& winbuild\\build\\build_dep_zlib.cmd"
 
+    - name: Build dependencies / xz
+      if: steps.build-cache.outputs.cache-hit != 'true'
+      run: "& winbuild\\build\\build_dep_xz.cmd"
+
+    - name: Build dependencies / WebP
+      if: steps.build-cache.outputs.cache-hit != 'true'
+      run: "& winbuild\\build\\build_dep_libwebp.cmd"
+
+    - name: Build dependencies / LibTiff
+      if: steps.build-cache.outputs.cache-hit != 'true'
+      run: "& winbuild\\build\\build_dep_libtiff.cmd"
+
+    # for FreeType CBDT/SBIX font support
+    - name: Build dependencies / libpng
+      if: steps.build-cache.outputs.cache-hit != 'true'
+      run: "& winbuild\\build\\build_dep_libpng.cmd"
+
+    # for FreeType WOFF2 font support
+    - name: Build dependencies / brotli
+      if: steps.build-cache.outputs.cache-hit != 'true'
+      run: "& winbuild\\build\\build_dep_brotli.cmd"
+
+    - name: Build dependencies / FreeType
+      if: steps.build-cache.outputs.cache-hit != 'true'
+      run: "& winbuild\\build\\build_dep_freetype.cmd"
+
+    - name: Build dependencies / LCMS2
+      if: steps.build-cache.outputs.cache-hit != 'true'
+      run: "& winbuild\\build\\build_dep_lcms2.cmd"
+
     - name: Build dependencies / OpenJPEG
       run: "& winbuild\\build\\build_dep_openjpeg.cmd"
 
+    # GPL licensed
+    - name: Build dependencies / libimagequant
+      if: steps.build-cache.outputs.cache-hit != 'true'
+      run: "& winbuild\\build\\build_dep_libimagequant.cmd"
+
+    # Raqm dependencies
+    - name: Build dependencies / HarfBuzz
+      if: steps.build-cache.outputs.cache-hit != 'true'
+      run: "& winbuild\\build\\build_dep_harfbuzz.cmd"
+
+    # Raqm dependencies
+    - name: Build dependencies / FriBidi
+      if: steps.build-cache.outputs.cache-hit != 'true'
+      run: "& winbuild\\build\\build_dep_fribidi.cmd"
+
     # trim ~150MB for each job
     - name: Optimize build cache
       if: steps.build-cache.outputs.cache-hit != 'true'
@@ -109,5 +180,5 @@ jobs:
     - name: Test Pillow
       run: |
         path %GITHUB_WORKSPACE%\\winbuild\\build\\bin;%PATH%
-        python.exe -c "from PIL import Image;im = Image.open('image');im.load()"
+        python.exe -m pytest -vx -W always --cov PIL --cov Tests --cov-report term --cov-report xml Tests
       shell: cmd
diff --git a/winbuild/build/src/openjpeg-2.5.2/src/lib/openjp2/openjpeg.c b/winbuild/build/src/openjpeg-2.5.2/src/lib/openjp2/openjpeg.c
index 01cce1767f5..382d8f4f0f1 100644
--- a/winbuild/build/src/openjpeg-2.5.2/src/lib/openjp2/openjpeg.c
+++ b/winbuild/build/src/openjpeg-2.5.2/src/lib/openjp2/openjpeg.c
@@ -593,7 +593,6 @@ OPJ_BOOL OPJ_CALLCONV opj_decode_tile_data(opj_codec_t *p_codec,
         opj_stream_t *p_stream
                                           )
 {
-    printf("torchwood\n");
     if (p_codec && p_data && p_stream) {
         opj_codec_private_t * l_codec = (opj_codec_private_t *) p_codec;
         opj_stream_private_t * l_stream = (opj_stream_private_t *) p_stream;
@@ -602,7 +601,6 @@ OPJ_BOOL OPJ_CALLCONV opj_decode_tile_data(opj_codec_t *p_codec,
             return OPJ_FALSE;
         }
 
-        printf("a\n");
         return l_codec->m_codec_data.m_decompression.opj_decode_tile_data(
                    l_codec->m_codec,
                    p_tile_index,
diff --git a/winbuild/build/src/openjpeg-2.5.2/src/lib/openjp2/t2.c b/winbuild/build/src/openjpeg-2.5.2/src/lib/openjp2/t2.c
index 2c233f0fb66..b921626c6d9 100644
--- a/winbuild/build/src/openjpeg-2.5.2/src/lib/openjp2/t2.c
+++ b/winbuild/build/src/openjpeg-2.5.2/src/lib/openjp2/t2.c
@@ -1175,6 +1175,9 @@ static OPJ_BOOL opj_t2_read_packet_header(opj_t2_t* p_t2,
         }
 
         l_header_length = (OPJ_UINT32)(l_header_data - *l_header_data_start);
+        if (!l_header_length) {
+            return OPJ_FALSE;
+        }
         *l_modified_length_ptr -= l_header_length;
         *l_header_data_start += l_header_length;