Cache test data on Azure Pipelines (#438)

Needed because Windows on Azure Pipelines can't fetch data from https://oceania.generic-mapping-tools.org/. Includes @earth_relief_10m, @earth_relief_60m, @ridge.txt, @Table_5_11.txt , @tut_bathy.nc, @tut_quakes.ngdc, and @tut_ship.xyz.

Co-authored-by: Dongdong Tian <seisman.info@gmail.com>

Author: weiji14

.azure-pipelines.yml

@@ -116,6 +116,22 @@ jobs:
       conda list
     displayName: List installed packages
 
+  # Cache the ${HOME}/.gmt directory, for docs and testing
+  - task: Cache@2
+    inputs:
+      key: cachedata | 20200519
+      path: $(HOME)/.gmt
+      cacheHitVar: CACHE_CACHEDATA_RESTORED
+    displayName: Cache GMT remote data for testing
+
+  # Download remote files, if not already cached
+  - bash: |
+      set -x -e
+      source activate testing
+      gmt which -Gu @earth_relief_10m @earth_relief_60m @ridge.txt @Table_5_11.txt @tut_bathy.nc @tut_quakes.ngdc @tut_ship.xyz
+    displayName: Download remote data
+    condition: ne(variables['CACHE_CACHEDATA_RESTORED'], true)
+
   # Install the package
   - bash: |
       set -x -e
@@ -198,6 +214,22 @@ jobs:
       conda list
     displayName: List installed packages
 
+  # Cache the ${HOME}/.gmt directory, for docs and testing
+  - task: Cache@2
+    inputs:
+      key: cachedata | 20200519
+      path: $(HOMEPATH)/.gmt
+      cacheHitVar: CACHE_CACHEDATA_RESTORED
+    displayName: Cache GMT remote data for testing
+
+  # Download remote files, if not already cached
+  - bash: |
+      set -x -e
+      source activate testing
+      gmt which -Gu @earth_relief_10m @earth_relief_60m @ridge.txt @Table_5_11.txt @tut_bathy.nc @tut_quakes.ngdc @tut_ship.xyz
+    displayName: Download remote data
+    condition: ne(variables['CACHE_CACHEDATA_RESTORED'], true)
+
   # Install the package that we want to test
   - bash: |
       set -x -e