Added github action to run tests

.github/workflows/run_tests.yml

@@ -0,0 +1,28 @@
+name: Python Package using Conda
+
+on: [push]
+
+jobs:
+  build-linux:
+    runs-on: ubuntu-latest
+    strategy:
+      max-parallel: 5
+
+    steps:
+    - uses: actions/checkout@v3
+    - name: Set up Python 3.10
+      uses: actions/setup-python@v3
+      with:
+        python-version: '3.10'
+    - name: Add conda to system path
+      run: |
+        # $CONDA is an environment variable pointing to the root of the miniconda directory
+        echo $CONDA/bin >> $GITHUB_PATH
+    - name: Install dependencies
+      run: |
+        conda env update --file environment.yml --name base
+        python -m pip install colossus
+    - name: Test with pytest
+      run: |
+        conda install pytest
+        pytest

environment.yml

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+name: szsims
+dependencies:
+  - numpy
+  - pandas
+  - astropy
+  - scipy