Reduce runtime of unit tests

[peanutfun]

Executing all CLIMADA unit tests takes between 4 to 5 minutes. I was wondering if we could reduce that a bit. The advantage would be that testing CLIMADA against multiple versions of Python would be more feasible, which in turn would make upgrading to new Python versions easier (see #596).

I executed the unit tests with duration reports and these are the tests that take the most time:

Unit Test Durations

============================================================================ slowest durations =============================================================================
16.14s call     climada/util/test/test_lines_polys_handler.py::TestGeomImpactCalcs::test_calc_geom_impact_polys
8.35s call     climada/hazard/test/test_storm_europe.py::TestReader::test_from_footprints
7.74s call     climada/engine/test/test_impact_data.py::TestEmdatProcessing::test_emdat_damage_yearlysum
6.42s call     climada/engine/test/test_impact_data.py::TestGDPScaling::test_scale_impact2refyear
5.38s call     climada/hazard/centroids/test/test_centr.py::TestCentroidsReader::test_base_grid
4.87s call     climada/entity/exposures/test/test_base.py::TestFuncs::test_assign_large_hazard_subset_pass
4.78s call     climada/hazard/test/test_base.py::TestCentroids::test_reproject_raster_pass
4.77s call     climada/util/test/test_plot.py::TestPlots::test_geo_scatter_categorical
4.64s call     climada/hazard/test/test_tc_tracks.py::TestIbtracs::test_ibtracs_with_basin
4.56s call     climada/engine/test/test_impact_data.py::TestEmdatToImpact::test_emdat_to_impact_scale
4.49s call     climada/engine/unsequa/test/test_unsequa.py::TestCalcCostBenefit::test_calc_uncertainty_pass
4.27s call     climada/hazard/test/test_base.py::TestHDF5::test_write_read_pass
4.12s call     climada/engine/unsequa/test/test_unsequa.py::TestOutput::test_plot_unc_cb
3.96s call     climada/util/test/test_coordinates.py::TestGetGeodata::test_on_land_pass
3.85s call     climada/hazard/test/test_base.py::TestCentroids::test_raster_to_vector_pass
3.28s call     climada/hazard/test/test_storm_europe.py::TestReader::test_generate_prob_storms
3.16s call     climada/engine/test/test_forecast.py::TestPlot::test_Forecast_plot
3.10s call     climada/entity/exposures/test/test_litpop.py::TestLitPop::test_get_total_value_per_country_gdp
2.86s call     climada/engine/test/test_impact_data.py::TestEmdatProcessing::test_emdat_impact_event_2018
2.83s call     climada/hazard/test/test_tc_tracks.py::TestFuncs::test_track_land_params
2.79s call     climada/hazard/test/test_tc_tracks_synth.py::TestSynth::test_cutoff_tracks
2.78s call     climada/engine/test/test_impact_data.py::TestEmdatProcessing::test_emdat_impact_event_2020
2.74s call     climada/engine/test/test_forecast.py::TestCalc::test_Forecast_init_raise
2.73s call     climada/hazard/test/test_tc_tracks.py::TestIbtracs::test_ibtracs_range
2.71s call     climada/hazard/test/test_storm_europe.py::TestReader::test_centroids_from_nc
2.67s call     climada/util/test/test_coordinates.py::TestRasterIO::test_transform_raster_pass
2.52s call     climada/util/test/test_lines_polys_handler.py::TestGdfGeomToPnt::test_gdf_poly_to_pnts
2.21s call     climada/engine/unsequa/test/test_unsequa.py::TestCalcCostBenefit::test_calc_sensitivity_pass
2.19s call     climada/entity/measures/test/test_base.py::TestApply::test_cutoff_hazard_region_pass
2.16s call     climada/engine/unsequa/test/test_unsequa.py::TestOutput::test_plot_unc_imp
2.08s call     climada/hazard/test/test_storm_europe.py::TestReader::test_set_ssi
1.99s call     climada/util/test/test_coordinates.py::TestGetGeodata::test_get_admin1_geometries_pass
1.98s call     climada/util/test/test_coordinates.py::TestGetGeodata::test_get_admin1_info_pass
1.98s call     climada/hazard/test/test_storm_europe.py::TestReader::test_read_with_ref
1.94s call     climada/util/test/test_finance.py::TestWBWealthAccount::test_tow_IND_1985_pass
1.93s call     climada/hazard/test/test_tc_tracks.py::TestIO::test_hdf5_io
1.91s call     climada/util/test/test_coordinates.py::TestGetGeodata::test_dist_to_coast
1.91s call     climada/hazard/test/test_storm_europe.py::TestReader::test_icon_read
1.91s call     climada/util/test/test_coordinates.py::TestRasterIO::test_crs_raster_pass
1.90s call     climada/entity/exposures/test/test_litpop.py::TestLitPop::test_get_total_value_per_country_pc
1.79s call     climada/hazard/test/test_tc_tracks.py::TestIbtracs::test_ibtracs_scale_wind
1.76s call     climada/util/test/test_plot.py::TestPlots::test_geo_im_from_array
1.73s call     climada/hazard/test/test_tc_tracks.py::TestIbtracs::test_ibtracs_interpolate_missing
1.68s call     climada/hazard/test/test_tc_tracks_synth.py::TestSynth::test_random_walk_single_point
1.61s call     climada/util/test/test_coordinates.py::TestRasterIO::test_crs_and_geometry_raster_pass
1.60s call     climada/entity/measures/test/test_base.py::TestApply::test_cutoff_hazard_pass
1.56s call     climada/hazard/centroids/test/test_vec_ras.py::TestRaster::test_dist_coast_pass
1.55s call     climada/hazard/test/test_tc_tracks.py::TestFuncs::test_subset
1.51s call     climada/entity/exposures/test/test_litpop.py::TestLitPop::test_grp_read_pass
1.48s call     climada/hazard/test/test_tc_tracks_synth.py::TestSynth::test_angle_funs_pass
1.43s call     climada/util/test/test_coordinates.py::TestGetGeodata::test_country_code_pass
1.42s call     climada/engine/test/test_impact.py::TestIO::test_excel_io
1.42s call     climada/hazard/test/test_tc_tracks_synth.py::TestSynth::test_random_walk_decay_pass
1.41s call     climada/engine/unsequa/test/test_unsequa.py::TestCalcCostBenefit::test_calc_uncertainty_pool_pass
1.34s call     climada/util/test/test_coordinates.py::TestGetGeodata::test_get_admin1_geometries_fail
1.27s call     climada/hazard/test/test_tc_tracks.py::TestIbtracs::test_ibtracs_with_provider
1.27s call     climada/hazard/centroids/test/test_vec_ras.py::TestVector::test_on_land
1.26s call     climada/hazard/test/test_tc_tracks.py::TestFuncs::test_tracks_in_exp_pass
1.24s call     climada/util/test/test_plot.py::TestPlots::test_geo_bin_from_array
1.22s call     climada/util/test/test_files.py::TestDownloadUrl::test_wrong_url_fail
1.14s call     climada/entity/exposures/test/test_base.py::TestAddSea::test_add_sea_pass
1.13s call     climada/engine/test/test_impact_calc.py::TestImpactCalc::test_calc_impact_RF_pass
1.10s call     climada/engine/test/test_cost_benefit.py::TestSteps::test_apply_transf_future_pass
1.08s call     climada/util/test/test_finance.py::TestWBWealthAccount::test_pca_CUB_2015_pass
1.08s call     climada/hazard/test/test_tc_tracks.py::TestFuncs::test_dist_since_lf_pass
1.05s call     climada/entity/exposures/test/test_litpop.py::TestLitPop::test_get_total_value_per_country_nfw
1.05s call     climada/util/test/test_finance.py::TestWBData::test_gdp_sxm_2010_pass
1.05s call     climada/util/test/test_coordinates.py::TestGetGeodata::test_get_country_geometries_country_norway_pass
1.01s call     climada/util/test/test_finance.py::TestWBData::test_wb_esp_1950_pass

(1860 durations < 1s hidden.  Use -vv to show these durations.)

How to replicate this on your machine:

conda activate climada_env
conda install pytest pytest-subtests
cd climada_python
pytest --durations=0 --durations-min=1 climada/engine/ climada/entity/ climada/hazard/ climada/util/

Looking at these numbers, I think it might be feasible to reduce the overall runtime of the unit tests by about 1 min. Options for reducing the run time include:

• Moving tests to the integration tests
• Reducing the amount of data to be loaded (e.g., self-made exemplary data instead of "real-world data")
• "Simplifying" tests (quotation marks because it is also unclear to me how each test could be simplified)

[peanutfun]

#709 reduced the runtime of all unit tests by about 1 min