added unit test

Readme.md

@@ -65,6 +65,7 @@ Here's what the environment variables mean:
 * `CELLXGENE_DATA` - a directory that can contain subdirectories with `.h5ad` data files, *without* trailing slash, e.g. `/mnt/cellxgene_data`
 * `GATEWAY_HOST` - the hostname and port that the gateway will run on, typically `localhost:5005` if running locally
 * `GATEWAY_PROTOCOL` - typically http when running locally, can be https when deployed if the gateway is behind a load balancer or reverse proxy.
+* `GATEWAY_EXTRA_SCRIPTS` - (optional) JSON array of script paths, will be embedded into each page and forwarded with `--scripts` to cellxgene server
 
 The defaults should be fine if you set up a venv and cellxgene_data folder as above.
 
@@ -73,11 +74,11 @@ The defaults should be fine if you set up a venv and cellxgene_data folder as ab
 The current paradigm for customization is to modify files during a build or deployment phase:
 
 * To modify CSS or JS on particular gateway pages, overwrite or append to the templates
-* To add script tags such as for user analytics to all pages, overwrite the extra_scripts.py file.
+* To add script tags such as for user analytics to all pages, set GATEWAY_EXTRA_SCRIPTS
   * these scripts will also be run on the pages served by cellxgene server via the --scripts parameter
   * See https://github.com/chanzuckerberg/cellxgene/pull/680 for details on --scripts parameter
 
-Currently we use a build.sh that copies the gateway to a "build" directory before modifying with sed and the like.
+Currently we use a bash script that copies the gateway to a "build" directory before modifying templates with sed and the like. There is probably a better way.
 
 # Development
 
@@ -106,6 +107,12 @@ python setup.py develop
 
 For convenience, the code repo includes a `run.sh.example` shell script to run the gateway.
 
+## Running Tests
+
+```bash
+    python -m unittest discover tests
+```
+
 ## Running Linters
 
 pip install isort flake8 black

cellxgene_gateway/env.py

@@ -24,21 +24,22 @@ env_vars = {
     "GATEWAY_IP": ip,
 }
 
-if not all(env_vars.values()):
-    raise ValueError(
-        f"""
-Please ensure that environment variables are set correctly.
-The ones with None below are missing and need to be set.
+def validate():
+    if not all(env_vars.values()):
+        raise ValueError(
+            f"""
+    Please ensure that environment variables are set correctly.
+    The ones with None below are missing and need to be set.
 
-{env_vars}
+    {env_vars}
 
-Set them at the terminal before running the gateway.
-An example is:
+    Set them at the terminal before running the gateway.
+    An example is:
 
-    export CELLXGENE_LOCATION=~/anaconda/envs/cellxgene-dev/bin/cellxgene
-    export CELLXGENE_DATA=../cellxgene_data
-    export GATEWAY_HOST=localhost:5005
-    export GATEWAY_PROTOCOL=http
-    export GATEWAY_IP=127.0.0.1
-"""
-    )
+        export CELLXGENE_LOCATION=~/anaconda/envs/cellxgene-dev/bin/cellxgene
+        export CELLXGENE_DATA=../cellxgene_data
+        export GATEWAY_HOST=localhost:5005
+        export GATEWAY_PROTOCOL=http
+        export GATEWAY_IP=127.0.0.1
+    """
+        )

cellxgene_gateway/extra_scripts.py

@@ -8,10 +8,11 @@
 # the specific language governing permissions and limitations under the License.
 
 from cellxgene_gateway import env
+from json import loads
 
 def get_extra_scripts():
     # can be array of script tags to inject on every page, e.g. for google analytics could be
     # ['https://www.googletagmanager.com/gtag/js?id=UA-123456-2',
     #  f"{env.gateway_protocol}://{env.gateway_host}/static/js/google_ua.js"]
     # where google_ua.js is a script you add to the static/js folder prior to deployment.
-    return [] if env.extra_scripts is None else [p.strip() for p in env.extra_scripts.split(",") if len(p.strip()) > 0]
+    return [] if env.extra_scripts is None else loads(env.extra_scripts)

cellxgene_gateway/gateway.py

@@ -184,6 +184,7 @@ def do_GET(path):
 
 
 def main():
+    env.validate()
     background_thread = Thread(target=PruneProcessCache(cache))
     background_thread.start()
 

tests/test_extra_scripts.py

+import unittest
+from unittest.mock import MagicMock, patch
+from cellxgene_gateway.extra_scripts import get_extra_scripts
+
+class TestExtraScripts(unittest.TestCase):
+    @patch('cellxgene_gateway.env.extra_scripts', new='["abc","def"]')
+    def test_GIVEN_two_scripts_THEN_returns_two_strings(self):
+        self.assertEqual(get_extra_scripts(), ['abc', 'def'])
+
+    @patch('cellxgene_gateway.env.extra_scripts', new='["abc", "def"]')
+    def test_GIVEN_two_scripts_space_THEN_returns_two_strings(self):
+        self.assertEqual(get_extra_scripts(), ['abc', 'def'])
+
+    @patch('cellxgene_gateway.env.extra_scripts', new=None)
+    def test_GIVEN_none_THEN_returns_empty_array(self):
+        self.assertEqual(get_extra_scripts(), [])
+
+    @patch('cellxgene_gateway.env.extra_scripts', new='[]')
+    def test_GIVEN_empty_string_THEN_returns_empty_array(self):
+        self.assertEqual(get_extra_scripts(), [])
+
+if __name__ == '__main__':
+    unittest.main()
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