What is the proper mechanism for separating build and test stages in azure-pipelines?

I have a toy C++ cmake project with the following azure-pipelines.yml (see HelloAzure for sources).

# Starter pipeline
# Start with a minimal pipeline that you can customize to build and deploy your code.
# Add steps that build, run tests, deploy, and more:
# https://aka.ms/yaml

trigger:
    - master 
variables:
  SOURCE_DIR: '$(System.DefaultWorkingDirectory)'
  BUILD_DIR: '$(SOURCE_DIR)/build'
  INSTALL_DIR: '$(SOURCE_DIR)/install'

stages:
  - stage: Build 
    displayName: Build 
    pool: 
      vmImage: ubuntu-latest    
    jobs:
      - job: BuildLinux 
        strategy:
          matrix:
            Release:
              BUILD_TYPE: 'Release'
            Debug:
              BUILD_TYPE: 'Debug'
        steps:
          - script: | 
              echo "mkdir BUILD_DIR $(BUILD_DIR)"
              mkdir $(BUILD_DIR)
              echo "cd build directory "
              cd $(BUILD_DIR)
              echo " Run configure command"
              cmake -DCMAKE_INSTALL_PREFIX=$(INSTALL_DIR)/$(BUILD_TYPE) $(SOURCE_DIR)
              echo "running cmake build command"
              cmake --build . --target install --config $(BUILD_TYPE) -j 12 
  - stage: BuildTests
    dependsOn: Build
    displayName: BuildTests 
    jobs: 
      - job: RunCTestLinux 
        steps: 
          - script: |
              cd $(BUILD_DIR)
              ctest

Locally I can do the following:

# download sources
git clone https://github.com/CiaranWelsh/HelloAzure.git

# build
cd HelloAzure
mkdir build
cd build
cmake -DCMAKE_INSTALL_PREFIX=../install ..
cmake --build . --target install --config Release -j 12

# test
ctest

I am trying to reproduce this workflow in azure. It is trivial to do using just one stage, but as soon as I try to run the tests in a "test" stage, Azure simply re-downloads the sources and tried to run the tests without first having ran the build command.

So my question, what is the proper mechanism for separating the build and test stages of a project in azure-pipelines?