diff --git a/.github/workflows/python-package.yml b/.github/workflows/python-package.yml
index a4843353c..a1178d956 100644
--- a/.github/workflows/python-package.yml
+++ b/.github/workflows/python-package.yml
@@ -5,7 +5,7 @@ name: OpenTimelineIO
 
 # for configuring which build will be a C++ coverage build / coverage report
 env:
-  GH_COV_PY: "3.10"
+  GH_COV_PY: "3.13"
   GH_COV_OS: ubuntu-latest
   GH_DEPENDABOT: dependabot
 
@@ -88,86 +88,120 @@ jobs:
           cd ${{ env.OTIO_CONSUMER_TEST_BUILD_DIR }}
           cmake ${{ github.workspace }}/tests/consumer -DCMAKE_PREFIX_PATH=${{ env.OTIO_INSTALL_DIR }}
 
-  py_build_test:
-    runs-on: ${{ matrix.os }}
+  py_smoketest_build:
+    # Ideally this would be ${{ env.GH_COV_OS }} - but github doens't allow it
+    runs-on: ubuntu-latest
     strategy:
       matrix:
-        os: [ubuntu-latest, windows-latest, macos-14, macos-latest]
         python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
-        include:
-          - { os: ubuntu-latest, shell: bash }
-          - { os: macos-latest, shell: bash }
-          - { os: macos-14, shell: bash }
-          - { os: windows-latest, shell: pwsh }
-          - { os: windows-latest, shell: msys2, python-version: "mingw64" }
-        exclude:
-          - { os: macos-latest, python-version: 3.9 }
 
     defaults:
       run:
-        shell: "${{ matrix.shell }} {0}"
+        shell: "bash {0}"
 
     env:
-      OTIO_CXX_COVERAGE_BUILD: ON
+      OTIO_CXX_COVERAGE_BUILD: 'ON'
       OTIO_CXX_BUILD_TMP_DIR: ${{ github.workspace }}/build
 
     steps:
-      - uses: actions/checkout@v4
+      - name: Get tests and requirements from source
+        uses: actions/checkout@v4
         with:
           submodules: "recursive"
-      - name: Set up MSYS2
-        if: matrix.python-version == 'mingw64'
-        uses: msys2/setup-msys2@v2
-        with:
-          msystem: mingw64
-          install: >-
-            mingw-w64-x86_64-python
-            mingw-w64-x86_64-python-pip
-            mingw-w64-x86_64-gcc
-            mingw-w64-x86_64-cmake
-            make
-            git
       - name: Set up Python ${{ matrix.python-version }}
-        if: matrix.python-version != 'mingw64'
         uses: actions/setup-python@v5.4.0
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install coverage dependency
-        if: matrix.python-version == env.GH_COV_PY && matrix.os == env.GH_COV_OS && github.actor != env.GH_DEPENDABOT
+        if: matrix.python-version == env.GH_COV_PY && github.actor != env.GH_DEPENDABOT
         run: |
           echo 'OTIO_CXX_DEBUG_BUILD=1' >> $GITHUB_ENV
           sudo apt-get install lcov
       - name: Install python build dependencies
         run: |
           python -m pip install --upgrade pip setuptools wheel "flake8>=3.5" check-manifest
-      # \todo Temporarily disable check-manifest on MinGW, it is failing
-      # intermittently with this error:
-      # ModuleNotFoundError: No module named 'pip._vendor.distlib'
       - name: Run check-manifest and lint check
-        if: matrix.python-version != 'mingw64'
         run: make ci-prebuild
-      - name: Build and Install
+      - name: Install test dependencies
+        run: |
+          python -m pip install --upgrade -r tests/requirements.txt
+      - name: Build and Install OpenTimelineIO
         run: |
-          pip install .[dev] -v --break-system-packages
+          python -m pip install . -v --break-system-packages
       - name: Run tests w/ python coverage
         run: make ci-postbuild
       # (only on GH_COV_OS and GH_COV_PY)
       - name: Generate C++ coverage report
-        if: matrix.python-version == env.GH_COV_PY && matrix.os == env.GH_COV_OS && github.actor != env.GH_DEPENDABOT
+        if: matrix.python-version == env.GH_COV_PY && github.actor != env.GH_DEPENDABOT
         run: make lcov
       - name: Upload coverage to Codecov
-        if: matrix.python-version == env.GH_COV_PY && matrix.os == env.GH_COV_OS && github.actor != env.GH_DEPENDABOT
-        uses: codecov/codecov-action@v4
+        if: matrix.python-version == env.GH_COV_PY && github.actor != env.GH_DEPENDABOT
+        uses: codecov/codecov-action@v5
         with:
           flags: py-unittests
           name: py-opentimelineio-codecov
           fail_ci_if_error: false
-        env:
-          # based on: https://github.com/codecov/codecov-action?tab=readme-ov-file#usage
-          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+          token: ${{ secrets.CODECOV_TOKEN }}
+          verbose: true
+
+  # This is for platforms where we build and test, but don't make wheels
+  py_testonly_build:
+    needs: package_sdist
+    # Ideally this would be ${{ env.GH_COV_OS }} - but github doens't allow it
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [windows-latest]
+        python-version: ["mingw64"]
+        include:
+          - { os: windows-latest, shell: msys2, python-version: "mingw64" }
+
+    defaults:
+      run:
+        shell: "${{ matrix.shell }} {0}"
+
+    env:
+      OTIO_CXX_COVERAGE_BUILD: 'ON'
+      OTIO_CXX_BUILD_TMP_DIR: ${{ github.workspace }}/build
+
+    steps:
+      - name: Set up MSYS2
+        if: matrix.python-version == 'mingw64'
+        uses: msys2/setup-msys2@v2
+        with:
+          msystem: mingw64
+          install: >-
+            mingw-w64-x86_64-python
+            mingw-w64-x86_64-python-pip
+            mingw-w64-x86_64-gcc
+            mingw-w64-x86_64-cmake
+            make
+            git
+      - name: Set up Python ${{ matrix.python-version }}
+        if: matrix.python-version != 'mingw64'
+        uses: actions/setup-python@v5.4.0
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Get sdist source
+        uses: actions/download-artifact@v5
+        with:
+          name: sdist
+          path: ./sdist
+      - name: Build and Install OpenTimelineIO
+        run: |
+          python -m pip install sdist/opentimelineio-*.tar.gz -v --break-system-packages
+      - name: Install python dev dependencies
+        run: |
+          python -m pip install --upgrade pip setuptools wheel "flake8>=3.5" check-manifest
+      - name: Get source
+        uses: actions/checkout@v4
+      - name: Install test dependencies
+        run: |
+          python -m pip install --break-system-packages --upgrade -r tests/requirements.txt
+      - name: Run tests w/ python coverage
+        run: make ci-postbuild
 
   package_wheels:
-    needs: py_build_test
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
@@ -182,6 +216,8 @@ jobs:
         python-build: ["cp39", "cp310", "cp311", "cp312", "cp313"]
     steps:
       - uses: actions/checkout@v4
+        with:
+          submodules: "recursive"
 
       - name: Build wheels (Python 3)
         uses: pypa/cibuildwheel@v3.2.1
@@ -200,8 +236,50 @@ jobs:
           name: wheel-${{ matrix.os }}-${{ matrix.python-build }}
           path: ./wheelhouse/*.whl
 
+  test_wheels:
+    needs: package_wheels
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-14, macos-latest]
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+        include:
+          - { os: ubuntu-latest, shell: bash }
+          - { os: macos-latest, shell: bash }
+          - { os: macos-14, shell: bash }
+          - { os: windows-latest, shell: pwsh }
+        exclude:
+          - { os: macos-latest, python-version: 3.9 }
+
+    defaults:
+      run:
+        shell: "${{ matrix.shell }} {0}"
+
+    env:
+      OTIO_CXX_COVERAGE_BUILD: 'ON'
+      OTIO_CXX_BUILD_TMP_DIR: ${{ github.workspace }}/build
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Python ${{ matrix.python-version }}
+        if: matrix.python-version != 'mingw64'
+        uses: actions/setup-python@v5.4.0
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Install python build dependencies
+        run: |
+          python -m pip install --upgrade pip setuptools wheel "flake8>=3.5" check-manifest && python -m pip install --upgrade -r tests/requirements.txt
+      - uses: actions/download-artifact@v5
+        with:
+          pattern: wheel-${{ matrix.os }}-*
+          path: 'wheelhouse'
+          merge-multiple: true
+      - name: Install wheel for environment
+        run: pip install --no-cache-dir --no-index --find-links wheelhouse opentimelineio
+      - name: Run tests w/ python coverage
+        run: make ci-postbuild
+
   package_sdist:
-    needs: py_build_test
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
diff --git a/Makefile b/Makefile
index f1fc21b07..7137f220f 100644
--- a/Makefile
+++ b/Makefile
@@ -16,7 +16,7 @@ ccend = $(shell echo "\033[0m")
 # Helpful link to install development dependencies declared in setup.py
 define dev_deps_message
 $(ccred)You can install this and other development dependencies with$(newline)$(ccend)\
-$(ccblue)	pip install -e .[dev]$(newline)$(ccend)
+$(ccblue)	pip install -e . && pip install -r tests/requirements.txt$(newline)$(ccend)
 endef
 
 # variables
diff --git a/setup.py b/setup.py
index 05f41963f..42b0668d1 100644
--- a/setup.py
+++ b/setup.py
@@ -371,14 +371,6 @@ def run(self):
             ),
         ],
     },
-    extras_require={
-        'dev': [
-            'check-manifest',
-            'flake8>=3.5',
-            'coverage>=4.5',
-            'urllib3>=1.24.3'
-        ],
-    },
 
     # because we need to open() the adapters manifest, we aren't zip-safe
     zip_safe=False,
diff --git a/tests/requirements.txt b/tests/requirements.txt
new file mode 100644
index 000000000..88a677c0b
--- /dev/null
+++ b/tests/requirements.txt
@@ -0,0 +1,4 @@
+check-manifest
+flake8>=3.5
+coverage>=4.5
+urllib3>=1.24.3