Get tests to pass on Azure Pipelines

.azure-pipelines.yml

@@ -5,34 +5,34 @@
 jobs:
 - job: Linux
   pool:
-    vmImage: ubuntu-16.04  
+    vmImage: ubuntu-16.04
   steps:
   - template: .azure-pipelines-steps.yml
 
-- job: Windows  
+- job: Windows
   pool:
-    vmImage: vs2017-win2016  
+    vmImage: vs2017-win2016
+  variables:
+    VSTS_OVERWRITE_TEMP: true
   steps:
-  - script: git config --global core.autocrlf false
-    displayName: 'Clone with LF preserved'
-
-  - script: choco install hg
-    displayName: 'Install Mercurial'
-
+  - script: |
+      git config --global core.autocrlf false
+      git config --global core.symlinks true
+    displayName: 'Preserve LF endings and symbolic links on check out'
   - template: .azure-pipelines-steps.yml
 
 - job: macOS
   pool:
     vmImage: macos-10.13
   steps:
   - script: brew install mercurial
-    displayName: 'Install Mercurial'    
-
+    displayName: 'Install Mercurial'
   - template: .azure-pipelines-steps.yml
 
 variables:
   # Ensures output produced by Jest for certain tests includes ANSI escape characters (needed to match snapshots)
   FORCE_COLOR: 1
   # Default checkout directory is "s", but inline snapshot tests will fail due to assumption that Jest is running under a "jest" folder
   # (see packages/jest-message-util/src/index.js PATH_JEST_PACKAGES)
-  JEST_DIR: $(Agent.BuildDirectory)/jest
+  JEST_DIR: $(Agent.BuildDirectory)/jest
+  CI: true