Fix taxi-runner.py cluster example (#2557)

* Added regression test
* Fix modin package installation

Signed-off-by: Anatoly Myachev <anatoly.myachev@intel.com>

modin/experimental/cloud/rayscale.py

@@ -167,6 +167,8 @@ def _conda_requirements(self):
                 reqs.append(self._get_modin_version())
 
             reqs.extend(self.add_conda_packages)
+        else:
+            reqs.append(self._get_modin_version())
 
         # this is needed, for example, for dependencies that
         # looks like: "scikit-learn>=0.23"

modin/experimental/cloud/test/test_cloud.py

@@ -107,23 +107,36 @@ def test_create_or_update_cluster(make_ray_cluster, make_create_or_update_cluste
         r"""conda create --clone base --name modin --yes
         conda activate modin
         conda install --yes {{CONDA_PACKAGES}}
-
-        pip install modin "ray==0.8.7" cloudpickle
         """
     ],
 )
-def test_update_conda_requirements(setup_commands_source, make_ray_cluster):
+@pytest.mark.parametrize(
+    "user_packages",
+    [
+        ["scikit-learn>=0.23", "modin==0.8.0"],
+        None,
+    ],
+)
+def test_update_conda_requirements(
+    make_ray_cluster,
+    setup_commands_source,
+    user_packages,
+):
     fake_version = namedtuple("FakeVersion", "major minor micro")(7, 12, 45)
     with mock.patch("sys.version_info", fake_version):
         setup_commands_result = make_ray_cluster(
-            ["scikit-learn>=0.23", "modin==0.8.0"]
+            user_packages
         )._update_conda_requirements(setup_commands_source)
 
     assert f"python>={fake_version.major}.{fake_version.minor}" in setup_commands_result
     assert (
         f"python<={fake_version.major}.{fake_version.minor}.{fake_version.micro}"
         in setup_commands_result
     )
-    assert "scikit-learn>=0.23" in setup_commands_result
-    assert "modin==0.8.0" in setup_commands_result
     assert "{{CONDA_PACKAGES}}" not in setup_commands_result
+
+    if user_packages:
+        for package in user_packages:
+            assert package in setup_commands_result
+    else:
+        assert "modin=" in setup_commands_result