diff --git a/.github/workflows/build-and-test-library.yml b/.github/workflows/build-and-test-library.yml
index 9152638d..10f75aca 100644
--- a/.github/workflows/build-and-test-library.yml
+++ b/.github/workflows/build-and-test-library.yml
@@ -6,8 +6,9 @@ on:
     - '.github/workflows/build-and-test-library.yml'
     - 'API/**'
     - 'CMake/FindZeta.cmake'
-    - 'sources/*.c'
-    - 'sources/*.rc.in'
+    - 'sources/test-Z80.c'
+    - 'sources/Z80.c'
+    - 'sources/Z80.rc.in'
     - 'support/*.sha3-512'
     - 'CMakeLists.txt'
   pull_request:
@@ -15,8 +16,9 @@ on:
     - '.github/workflows/build-and-test-library.yml'
     - 'API/**'
     - 'CMake/FindZeta.cmake'
-    - 'sources/*.c'
-    - 'sources/*.rc.in'
+    - 'sources/test-Z80.c'
+    - 'sources/Z80.c'
+    - 'sources/Z80.rc.in'
     - 'support/*.sha3-512'
     - 'CMakeLists.txt'
 
diff --git a/.github/workflows/step-tests.yml b/.github/workflows/step-tests.yml
new file mode 100644
index 00000000..b9cdfe8d
--- /dev/null
+++ b/.github/workflows/step-tests.yml
@@ -0,0 +1,92 @@
+name: Step tests
+
+on:
+  push:
+    paths:
+    - '.github/workflows/step-tests.yml'
+    - 'API/**'
+    - 'CMake/FindZeta.cmake'
+    - 'sources/step-test-Z80.c'
+    - 'sources/Z80.c'
+    - 'CMakeLists.txt'
+  pull_request:
+    paths:
+    - '.github/workflows/step-tests.yml'
+    - 'API/**'
+    - 'CMake/FindZeta.cmake'
+    - 'sources/step-test-Z80.c'
+    - 'sources/Z80.c'
+    - 'CMakeLists.txt'
+
+env:
+  BUILD_SHARED_LIBS: YES
+  CMAKE_BUILD_TYPE: Release
+  Z80_FETCH_TEST_FILES: YES
+  Z80_NOSTDLIB_FLAGS: Auto
+  Z80_WITH_CMAKE_SUPPORT: NO
+  Z80_WITH_HTML_DOCUMENTATION: NO
+  Z80_WITH_PDF_DOCUMENTATION: NO
+  Z80_WITH_PKGCONFIG_SUPPORT: NO
+  Z80_WITH_STANDARD_DOCUMENTS: NO
+  Z80_WITH_STEP_TESTS: YES
+  Z80_WITH_TESTS: NO
+  Z80_WITH_EXECUTE: YES
+  Z80_WITH_FULL_IM0: YES
+  Z80_WITH_IM0_RETX_NOTIFICATIONS: YES
+  Z80_WITH_Q: YES
+  Z80_WITH_SPECIAL_RESET: YES
+  Z80_WITH_UNOFFICIAL_RETI: NO
+  Z80_WITH_ZILOG_NMOS_LD_A_IR_BUG: YES
+
+jobs:
+  step-tests:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Install dependencies
+      run: |
+        curl -L https://zxe.io/scripts/add-zxe-apt-repo.sh | sudo sh
+        sudo apt-get update
+        sudo apt-get -y install libcjson-dev
+        sudo apt-get -y install libz80insnclock-dev
+
+    - name: Fetch unit tests
+      run: |
+        mkdir -p "${{github.workspace}}/build/SingleStepTests-Z80"
+        curl -L $(
+          curl -s https://api.github.com/repos/SingleStepTests/z80/releases/latest |
+          grep tarball_url | cut -d : -f 2,3 | tr -d '" ,'
+        ) | gzip -cd | tar -C "${{github.workspace}}/build/SingleStepTests-Z80" --strip-components=2 -xf - "SingleStepTests**/v1"
+
+    - name: Configure CMake
+      run: >-
+        cmake
+        -DBUILD_SHARED_LIBS=${{env.BUILD_SHARED_LIBS}}
+        -DCMAKE_BUILD_TYPE=${{env.CMAKE_BUILD_TYPE}}
+        -DZ80_FETCH_TEST_FILES=${{env.Z80_FETCH_TEST_FILES}}
+        -DZ80_NOSTDLIB_FLAGS=${{env.Z80_NOSTDLIB_FLAGS}}
+        -DZ80_WITH_CMAKE_SUPPORT=${{env.Z80_WITH_CMAKE_SUPPORT}}
+        -DZ80_WITH_HTML_DOCUMENTATION=${{env.Z80_WITH_HTML_DOCUMENTATION}}
+        -DZ80_WITH_PDF_DOCUMENTATION=${{env.Z80_WITH_PDF_DOCUMENTATION}}
+        -DZ80_WITH_PKGCONFIG_SUPPORT=${{env.Z80_WITH_PKGCONFIG_SUPPORT}}
+        -DZ80_WITH_STANDARD_DOCUMENTS=${{env.Z80_WITH_STANDARD_DOCUMENTS}}
+        -DZ80_WITH_STEP_TESTS=${{env.Z80_WITH_STEP_TESTS}}
+        -DZ80_WITH_TESTS=${{env.Z80_WITH_TESTS}}
+        -DZ80_WITH_EXECUTE=${{env.Z80_WITH_EXECUTE}}
+        -DZ80_WITH_FULL_IM0=${{env.Z80_WITH_FULL_IM0}}
+        -DZ80_WITH_IM0_RETX_NOTIFICATIONS=${{env.Z80_WITH_IM0_RETX_NOTIFICATIONS}}
+        -DZ80_WITH_Q=${{env.Z80_WITH_Q}}
+        -DZ80_WITH_SPECIAL_RESET=${{env.Z80_WITH_SPECIAL_RESET}}
+        -DZ80_WITH_UNOFFICIAL_RETI=${{env.Z80_WITH_UNOFFICIAL_RETI}}
+        -DZ80_WITH_ZILOG_NMOS_LD_A_IR_BUG=${{env.Z80_WITH_ZILOG_NMOS_LD_A_IR_BUG}}
+        -B "${{github.workspace}}/build"
+        -S "${{github.workspace}}"
+
+    - name: Build
+      run: cmake --build "${{github.workspace}}/build" --config ${{env.CMAKE_BUILD_TYPE}} --verbose
+
+    - name: Test
+      working-directory: ${{github.workspace}}/build
+      run: ./step-test-Z80 SingleStepTests-Z80/*.json
diff --git a/README.md b/README.md
index 428dc183..c8c4cc0f 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,7 @@
 
 [![](https://zxe.io/software/Z80/assets/images/documentation-badge.svg)](https://zxe.io/software/Z80/documentation/latest)
 [![](https://github.com/redcode/Z80/actions/workflows/build-and-test-library.yml/badge.svg)](https://github.com/redcode/Z80/actions/workflows/build-and-test-library.yml)
+[![](https://github.com/redcode/Z80/actions/workflows/step-tests.yml/badge.svg)](https://github.com/redcode/Z80/actions/workflows/step-tests.yml)
 [![](https://github.com/redcode/Z80/actions/workflows/build-documentation.yml/badge.svg)](https://github.com/redcode/Z80/actions/workflows/build-documentation.yml)
 [![](https://zxe.io/software/Z80/assets/images/chat-badge.svg)](https://zxe.io/software/Z80/chat)
 ![](https://zxe.io/software/Z80/assets/images/mentioned-in-awesome-badge.svg)