CI: Split build and test into separate jobs

This will give us more flexibility later, e.g. allowing different steps
for GCC and Clang (as needed for code coverage), or letting us
parallelise our tests across multiple machines.

.circleci/config.yml

@@ -1,22 +1,41 @@
 version: 2.1
 
 workflows:
-  build-test:
+  object-introspection:
     jobs:
       - lint
-      - build-test:
-          name: build-test-gcc
+
+      - build:
+          name: build-gcc
           cc: /usr/bin/gcc
           cxx: /usr/bin/g++
-      - build-test:
-          name: build-test-clang
+      - test:
+          name: test-gcc
+          requires:
+            - build-gcc
+
+      - build:
+          name: build-clang
           cc: /usr/bin/clang-12
           cxx: /usr/bin/clang++-12
+      - test:
+          name: test-clang
+          requires:
+            - build-clang
+
+executors:
+  ubuntu-docker:
+    docker:
+      - image: ubuntu:jammy
+    resource_class: small
+  big-boy:
+    machine:
+      image: ubuntu-2204:2022.10.2
+    resource_class: 2xlarge
 
 jobs:
   lint:
-    docker:
-      - image: ubuntu:jammy
+    executor: ubuntu-docker
     steps:
       - run:
           name: Install dependencies
@@ -42,10 +61,9 @@ jobs:
             black --check --diff test/
             isort --check --diff test/
 
-  build-test:
-    machine:
-      image: ubuntu-2204:2022.10.2
-    resource_class: 2xlarge
+  build:
+    # TODO this job could be run in Docker
+    executor: big-boy
     parameters:
       cc:
         type: string
@@ -55,11 +73,9 @@ jobs:
       CC: << parameters.cc >>
       CXX: << parameters.cxx >>
     steps:
-      - checkout
       - run:
           name: Install dependencies
           command: |
-            sudo rm -f /etc/apt/sources.list.d/heroku.list
             sudo apt-get update
             sudo apt-get install -y \
               bison \
@@ -90,13 +106,34 @@ jobs:
             pip3 install toml
           environment:
             DEBIAN_FRONTEND: noninteractive
-
+      - checkout
       - run:
           name: Build
           command: |
             cmake -G Ninja -B build/ -DWITH_TESTS=On
-            cmake --build build/ -j
+            cmake --build build/
+            # Testing rubbish:
+            cp test/ci.oid.toml build/testing.oid.toml
+      - persist_to_workspace:
+          root: .
+          paths:
+            - build/*
+            - extern/*
+            - types/*
 
+  test:
+    executor: big-boy
+    steps:
+      - attach_workspace:
+          at: .
+      - run:
+          name: Install dependencies
+          command: |
+            sudo apt-get update
+            sudo apt-get install -y \
+              clang-12 \
+              libgflags-dev \
+              llvm-12-dev
       - run:
           name: Test
           environment:
@@ -104,7 +141,6 @@ jobs:
             OMP_NUM_THREADS: 1
           command: |
             echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope
-            cp test/ci.oid.toml build/testing.oid.toml
             ctest --test-dir build/test/ --test-action Test -j$(nproc) \
               --no-compress-output --output-on-failure \
               --exclude-regex 'TestTypes\/ComparativeTest\..*' \