diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 6f2bcf5..88fdace 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -43,33 +43,6 @@ jobs:
         cache: 'pip'
         cache-dependency-path: 'pyproject.toml'
 
-    # Needed for `pueblo.ngr`.
-    - name: Set up Elixir
-      uses: erlef/setup-beam@v1
-      with:
-        otp-version: '22.2'
-        elixir-version: '1.9.4'
-    - name: Retrieve Mix Dependencies Cache
-      uses: actions/cache@v3
-      id: elixir-mix-cache
-      with:
-        path: tests/ngr/elixir/deps
-        key: ${{ runner.os }}-${{ matrix.otp }}-${{ matrix.elixir }}-mix-${{ hashFiles(format('{0}{1}', github.workspace, '/mix.lock')) }}
-
-    # Needed for `pueblo.ngr`.
-    - name: Set up Java
-      uses: actions/setup-java@v3
-      with:
-        distribution: "temurin"
-        java-version: "17"
-
-    # Needed for `pueblo.ngr`.
-    - name: Set up Ruby
-      uses: ruby/setup-ruby@v1
-      with:
-        ruby-version: "3.2"
-        bundler-cache: true
-
     - name: Set up project
       run: |
 
diff --git a/.github/workflows/ngr.yml b/.github/workflows/ngr.yml
new file mode 100644
index 0000000..9a89b75
--- /dev/null
+++ b/.github/workflows/ngr.yml
@@ -0,0 +1,103 @@
+---
+name: Tests for pueblo.ngr
+
+on:
+  pull_request:
+    branches: ~
+    paths:
+    - '.github/workflows/ngr.yml'
+    - 'pueblo/ngr/**'
+    - 'tests/ngr/**'
+  push:
+    branches: [ main ]
+    paths:
+    - '.github/workflows/ngr.yml'
+    - 'pueblo/ngr/**'
+    - 'tests/ngr/**'
+
+  # Allow job to be triggered manually.
+  workflow_dispatch:
+
+# Cancel in-progress jobs when pushing to the same branch.
+concurrency:
+  cancel-in-progress: true
+  group: ${{ github.workflow }}-${{ github.ref }}
+
+jobs:
+
+  tests:
+
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: ["ubuntu-latest"]
+        python-version: ["3.11"]
+
+    env:
+      OS: ${{ matrix.os }}
+      PYTHON: ${{ matrix.python-version }}
+
+    name: Python ${{ matrix.python-version }} on OS ${{ matrix.os }}
+    steps:
+
+    - name: Acquire sources
+      uses: actions/checkout@v4
+
+    - name: Set up Python
+      uses: actions/setup-python@v4
+      with:
+        python-version: ${{ matrix.python-version }}
+        architecture: x64
+        cache: 'pip'
+        cache-dependency-path: 'pyproject.toml'
+
+    # Needed for `pueblo.ngr`.
+    - name: Set up Elixir
+      uses: erlef/setup-beam@v1
+      with:
+        otp-version: '26.1'
+        elixir-version: '1.15'
+    - name: Retrieve Mix Dependencies Cache
+      uses: actions/cache@v3
+      id: elixir-mix-cache
+      with:
+        path: tests/ngr/elixir/deps
+        key: ${{ runner.os }}-${{ matrix.otp }}-${{ matrix.elixir }}-mix-${{ hashFiles(format('{0}{1}', github.workspace, '/mix.lock')) }}
+
+    # Needed for `pueblo.ngr`.
+    - name: Set up Java
+      uses: actions/setup-java@v3
+      with:
+        distribution: "temurin"
+        java-version: "17"
+
+    # Needed for `pueblo.ngr`.
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: "3.2"
+        bundler-cache: true
+
+    - name: Set up project
+      run: |
+
+        # `setuptools 0.64.0` adds support for editable install hooks (PEP 660).
+        # https://github.com/pypa/setuptools/blob/main/CHANGES.rst#v6400
+        pip install --upgrade 'setuptools>=64'
+
+        # Install package in editable mode.
+        pip install --use-pep517 --prefer-binary --editable='.[all,develop,test]'
+
+    - name: Run linter and software tests
+      run: |
+        pytest -m ngr
+
+    - name: Upload coverage to Codecov
+      uses: codecov/codecov-action@v3
+      with:
+        files: ./coverage.xml
+        flags: unittests
+        env_vars: OS,PYTHON
+        name: codecov-umbrella
+        fail_ci_if_error: false
diff --git a/pyproject.toml b/pyproject.toml
index 53a6927..c91448a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -140,6 +140,7 @@ log_cli_level = "DEBUG"
 testpaths = ["tests"]
 xfail_strict = true
 markers = [
+  "ngr",
 ]
 
 [tool.coverage.run]
@@ -230,11 +231,11 @@ lint = [
   { cmd = "validate-pyproject pyproject.toml" },
   { cmd = "mypy" },
 ]
-test = [
-  { cmd = "pytest" },
-]
+test = "pytest -m 'not ngr'"
+test-full = "pytest"
 build = { cmd = "python -m build" }
 check = ["lint", "test"]
+check-full = ["lint", "test-full"]
 
 release = [
   { cmd = "python -m build" },
diff --git a/tests/test_ngr.py b/tests/test_ngr.py
index 1df6225..54846be 100644
--- a/tests/test_ngr.py
+++ b/tests/test_ngr.py
@@ -12,6 +12,7 @@
 HERE = Path(__file__).parent
 
 
+@pytest.mark.ngr
 def test_ngr_version():
     """
     Invoke `ngr --version`.
@@ -36,6 +37,7 @@ def list_target_samples(path: Path):
     return [sample for sample in samples if ".pytest_cache" not in str(sample)]
 
 
+@pytest.mark.ngr
 @pytest.mark.parametrize("sample", list_target_samples(HERE), ids=map(str, list_target_samples(HERE)))
 def test_ngr_sample(sample: Path):
     """