diff --git a/libs/experimental/tests/unit_tests/conftest.py b/libs/experimental/tests/unit_tests/conftest.py
new file mode 100644
index 0000000000..da45a330f5
--- /dev/null
+++ b/libs/experimental/tests/unit_tests/conftest.py
@@ -0,0 +1,83 @@
+"""Configuration for unit tests."""
+from importlib import util
+from typing import Dict, Sequence
+
+import pytest
+from pytest import Config, Function, Parser
+
+
+def pytest_addoption(parser: Parser) -> None:
+    """Add custom command line options to pytest."""
+    parser.addoption(
+        "--only-extended",
+        action="store_true",
+        help="Only run extended tests. Does not allow skipping any extended tests.",
+    )
+    parser.addoption(
+        "--only-core",
+        action="store_true",
+        help="Only run core tests. Never runs any extended tests.",
+    )
+
+
+def pytest_collection_modifyitems(config: Config, items: Sequence[Function]) -> None:
+    """Add implementations for handling custom markers.
+
+    At the moment, this adds support for a custom `requires` marker.
+
+    The `requires` marker is used to denote tests that require one or more packages
+    to be installed to run. If the package is not installed, the test is skipped.
+
+    The `requires` marker syntax is:
+
+    .. code-block:: python
+
+        @pytest.mark.requires("package1", "package2")
+        def test_something():
+            ...
+    """
+    # Mapping from the name of a package to whether it is installed or not.
+    # Used to avoid repeated calls to `util.find_spec`
+    required_pkgs_info: Dict[str, bool] = {}
+
+    only_extended = config.getoption("--only-extended") or False
+    only_core = config.getoption("--only-core") or False
+
+    if only_extended and only_core:
+        raise ValueError("Cannot specify both `--only-extended` and `--only-core`.")
+
+    for item in items:
+        requires_marker = item.get_closest_marker("requires")
+        if requires_marker is not None:
+            if only_core:
+                item.add_marker(pytest.mark.skip(reason="Skipping not a core test."))
+                continue
+
+            # Iterate through the list of required packages
+            required_pkgs = requires_marker.args
+            for pkg in required_pkgs:
+                # If we haven't yet checked whether the pkg is installed
+                # let's check it and store the result.
+                if pkg not in required_pkgs_info:
+                    required_pkgs_info[pkg] = util.find_spec(pkg) is not None
+
+                if not required_pkgs_info[pkg]:
+                    if only_extended:
+                        pytest.fail(
+                            f"Package `{pkg}` is not installed but is required for "
+                            f"extended tests. Please install the given package and "
+                            f"try again.",
+                        )
+
+                    else:
+                        # If the package is not installed, we immediately break
+                        # and mark the test as skipped.
+                        item.add_marker(
+                            pytest.mark.skip(reason=f"Requires pkg: `{pkg}`")
+                        )
+                        break
+        else:
+            if only_extended:
+                item.add_marker(
+                    pytest.mark.skip(reason="Skipping not an extended test.")
+                )