Merge PR #286 (Add GitHub action to build GCPy env)

This merge brings PR #286 (Add GitHub action to build GCPy environment
and test installation, by @yantosca) into the GCPy 1.4.2 development
stream.

This adds a GitHub action to check if the GCPy environment (as specified
in the "environment.yml" file) will build properly, and if the "import gcpy"
command works.

Signed-off-by: Bob Yantosca <[email protected]>

.github/workflows/build-gcpy-environment.yml

@@ -0,0 +1,39 @@
+---
+#
+# GitHub action to build the GCPy environment with micromamba
+# See: https://github.com/marketplace/actions/setup-micromamba
+#
+name: build-gcpy-environment
+
+on:
+  push:
+    branches: [ "main", "dev" ]
+  pull_request:
+    # The branches below must be a subset of the branches above
+    branches: [ "main", "dev" ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.9"]
+    steps:
+      - name: Checkout the GCPy repository
+        uses: actions/checkout@v2
+      - name: Create the GCPy environment
+        uses: mamba-org/setup-micromamba@v1
+        with:
+          micromamba-version: 'latest'
+          environment-file: environment.yml
+          environment-name: gcpy-test-env
+          init-shell: bash
+          cache-environment: true
+          generate-run-shell: true
+          post-cleanup: 'all'
+      - name: Test if "import gcpy" works
+        run: python -c "import gcpy"
+        shell: micromamba-shell {0}
+      - name: Test if we can create a plot
+        run: python -m gcpy.examples.plotting.create_test_plot
+        shell: micromamba-shell {0}

CHANGELOG.md

@@ -4,6 +4,11 @@ All notable changes to GCPy will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/), and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased] - TBD
+### Added
+- Example script `create_test_plot.py`, which can be used to check that GCPy has been installed properly
+- GitHub action `build-gcpy-environment` which tests installation of the mamba environment specified in in `docs/source/environment.yml`
+
 ## [1.4.1] - 2023-12-08
 ### Fixed
 - Now use the proper default value for the `--weightsdir` argument to `gcpy/file_regrid.py`

gcpy/examples/plotting/__init__.py

@@ -1,5 +1,6 @@
 """
 GCPy import script
 """
+from .create_test_plot import *
 from .plot_single_panel import *
 from .plot_comparisons import *

gcpy/examples/plotting/create_test_plot.py

@@ -0,0 +1,55 @@
+#!/usr/bin/env python
+
+"""
+Creates a dummy xarray DataArray object for testing the single_panel
+plotting routine.  This script can be a useful check to see whether the
+GCPy mamba/conda environment has been successfully installed.
+"""
+
+import numpy as np
+import xarray as xr
+import matplotlib.pyplot as plt
+import gcpy
+
+
+def main():
+    """
+    Main program: Creates a dummy plot
+    """
+
+    # Get X and Y coordinate arrays
+    n_lat = 181
+    n_lon = 361
+    lat_vals = np.linspace(-90, 90, n_lat)
+    lon_vals = np.linspace(-180, 180, n_lon)
+
+    # Create a dummy numpy array for plotting
+    # Populate it with the distance from the center of the plot
+    data = np.zeros([n_lat, n_lon])
+    for lat in range(n_lat):
+        for lon in range(n_lon):
+            data[lat, lon] = np.sqrt(lon_vals[lon]**2 + lat_vals[lat]**2)
+
+    # Create a Dataarray from the numpy array
+    darr = xr.DataArray(
+        data=data,
+        dims=["lat", "lon"],
+        coords=dict(
+            lat=("lat", lat_vals),
+            lon=("lon", lon_vals),
+        ),
+    )
+
+    # Create a plot
+    gcpy.plot.single_panel(
+        darr,
+        plot_type="single_level",
+        title="Test plot to check GCPy import",
+        extent=[-180, 180, -90, 90],
+        comap=plt.get_cmap("RdBu_r")
+    )
+    plt.show()
+
+
+if __name__ == '__main__':
+    main()