From d83c036ef1ea3131d0ba14cb964485039509dd82 Mon Sep 17 00:00:00 2001
From: Pierre de La Morinerie <kemenaran@gmail.com>
Date: Tue, 19 Oct 2021 18:09:03 +0200
Subject: [PATCH 1/9] specs: profile specs runtime

---
 .rspec | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.rspec b/.rspec
index 0f30adeb0..d958652df 100644
--- a/.rspec
+++ b/.rspec
@@ -1,2 +1,3 @@
 --color
 --require rails_helper
+--profile

From 21efece09e1cf985fe15296da8cca2a6ed866912 Mon Sep 17 00:00:00 2001
From: Pierre de La Morinerie <kemenaran@gmail.com>
Date: Tue, 26 Oct 2021 11:07:42 +0000
Subject: [PATCH 2/9] ci: use builtin cache for node modules

This is around 20s faster (10s when retrieved the cache and installing
node modules, and 10s when saving the cache).
---
 .github/workflows/ci.yml | 34 ++++++++--------------------------
 1 file changed, 8 insertions(+), 26 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 47554ed09..eac5a92b7 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -22,19 +22,10 @@ jobs:
         uses: actions/setup-node@v2
         with:
           node-version: '14'
-      - name: Find yarn cache location
-        id: yarn-cache
-        run: echo "::set-output name=dir::$(yarn cache dir)"
-      - name: JS package cache
-        uses: actions/cache@v2
-        with:
-          path: ${{ steps.yarn-cache.outputs.dir }}
-          key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-yarn-
-      - name: Install packages
-        run: |
-          yarn install --frozen-lockfile
+          cache: yarn
+
+      - name: Install node modules
+        run: yarn install --frozen-lockfile
 
       - name: Run linters
         run: |
@@ -79,19 +70,10 @@ jobs:
         uses: actions/setup-node@v2
         with:
           node-version: '14'
-      - name: Find yarn cache location
-        id: yarn-cache
-        run: echo "::set-output name=dir::$(yarn cache dir)"
-      - name: JS package cache
-        uses: actions/cache@v2
-        with:
-          path: ${{ steps.yarn-cache.outputs.dir }}
-          key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-yarn-
-      - name: Install packages
-        run: |
-          yarn install --frozen-lockfile
+          cache: 'yarn'
+
+      - name: Install Node modules
+        run: yarn install --frozen-lockfile
 
       - name: Setup test database
         env:

From ba78e2bfb2a19c48299efa13e15ec2ff916fb545 Mon Sep 17 00:00:00 2001
From: Pierre de La Morinerie <kemenaran@gmail.com>
Date: Tue, 26 Oct 2021 13:27:26 +0200
Subject: [PATCH 3/9] ci: use bin/rails instead of rake

---
 .github/workflows/ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index eac5a92b7..ef3df3965 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -80,7 +80,7 @@ jobs:
           RAILS_ENV: test
           DATABASE_URL: "postgres://tps_test@localhost:5432/tps_test"
         run: |
-          bundle exec rake db:create db:schema:load db:migrate
+          bin/rails db:create db:schema:load db:migrate
 
       - name: Setup environment variables
         run: |

From 2c96ade1b2ce6148884e5fb4592b7dcb0b89c08b Mon Sep 17 00:00:00 2001
From: Pierre de La Morinerie <kemenaran@gmail.com>
Date: Tue, 26 Oct 2021 12:01:56 +0000
Subject: [PATCH 4/9] ci: split tests automatically

---
 .github/workflows/ci.yml | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ef3df3965..468dad6dc 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -47,15 +47,14 @@ jobs:
       matrix:
         pattern:
           - bin/rake zeitwerk:check
-          - bin/rspec spec/controllers/*_spec.rb
-          - bin/rspec spec/controllers/[a-l]**/*_spec.rb
-          - bin/rspec spec/controllers/[m-z]**/*_spec.rb
-          - bin/rspec spec/system
-          - bin/rspec spec/helpers spec/lib spec/middlewares
-          - bin/rspec spec/mailers spec/jobs spec/policies
-          - bin/rspec spec/models
-          - bin/rspec spec/serializers spec/services
-          - bin/rspec spec/views
+          - bin/rspec $(./split_tests -line-count -glob='spec/**/*_spec.rb' -exclude-glob='spec/system/**' -split-index=0 -split-total=6)
+          - bin/rspec $(./split_tests -line-count -glob='spec/**/*_spec.rb' -exclude-glob='spec/system/**' -split-index=1 -split-total=6)
+          - bin/rspec $(./split_tests -line-count -glob='spec/**/*_spec.rb' -exclude-glob='spec/system/**' -split-index=2 -split-total=6)
+          - bin/rspec $(./split_tests -line-count -glob='spec/**/*_spec.rb' -exclude-glob='spec/system/**' -split-index=3 -split-total=6)
+          - bin/rspec $(./split_tests -line-count -glob='spec/**/*_spec.rb' -exclude-glob='spec/system/**' -split-index=4 -split-total=6)
+          - bin/rspec $(./split_tests -line-count -glob='spec/**/*_spec.rb' -exclude-glob='spec/system/**' -split-index=5 -split-total=6)
+          - bin/rspec $(./split_tests -line-count -glob='spec/system/**/*_spec.rb' -split-index=0 -split-total=2)
+          - bin/rspec $(./split_tests -line-count -glob='spec/system/**/*_spec.rb' -split-index=1 -split-total=2)
 
     steps:
       - name: Checkout code
@@ -75,6 +74,11 @@ jobs:
       - name: Install Node modules
         run: yarn install --frozen-lockfile
 
+      - name: Setup split_tests binary
+        run: |
+          curl --no-progress-meter -L https://github.com/leonid-shevtsov/split_tests/releases/download/v0.3.0/split_tests.linux.gz | gunzip -c > split_tests
+          chmod +x split_tests
+
       - name: Setup test database
         env:
           RAILS_ENV: test

From a01a619ec050d0b1db8bf516a5ff857f569efc38 Mon Sep 17 00:00:00 2001
From: Pierre de La Morinerie <kemenaran@gmail.com>
Date: Tue, 26 Oct 2021 14:38:40 +0200
Subject: [PATCH 5/9] js: update caniuse browsers db

This follows a warning during tests:

> Browserslist: caniuse-lite is outdated. Please run:
> npx browserslist@latest --update-db
>
> Why you should do it regularly:
> browserslist/browserslist#browsers-data-updating
---
 yarn.lock | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/yarn.lock b/yarn.lock
index 1361a306e..f7e857088 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3525,15 +3525,10 @@ caniuse-api@^3.0.0:
     lodash.memoize "^4.1.2"
     lodash.uniq "^4.5.0"
 
-caniuse-lite@^1.0.0, caniuse-lite@^1.0.30000981, caniuse-lite@^1.0.30001039, caniuse-lite@^1.0.30001219:
-  version "1.0.30001228"
-  resolved "https://registry.yarnpkg.com/caniuse-lite/-/caniuse-lite-1.0.30001228.tgz#bfdc5942cd3326fa51ee0b42fbef4da9d492a7fa"
-  integrity sha512-QQmLOGJ3DEgokHbMSA8cj2a+geXqmnpyOFT0lhQV6P3/YOJvGDEwoedcwxEQ30gJIwIIunHIicunJ2rzK5gB2A==
-
-caniuse-lite@^1.0.30001254:
-  version "1.0.30001257"
-  resolved "https://registry.yarnpkg.com/caniuse-lite/-/caniuse-lite-1.0.30001257.tgz#150aaf649a48bee531104cfeda57f92ce587f6e5"
-  integrity sha512-JN49KplOgHSXpIsVSF+LUyhD8PUp6xPpAXeRrrcBh4KBeP7W864jHn6RvzJgDlrReyeVjMFJL3PLpPvKIxlIHA==
+caniuse-lite@^1.0.0, caniuse-lite@^1.0.30000981, caniuse-lite@^1.0.30001039, caniuse-lite@^1.0.30001219, caniuse-lite@^1.0.30001254:
+  version "1.0.30001271"
+  resolved "https://registry.npmjs.org/caniuse-lite/-/caniuse-lite-1.0.30001271.tgz"
+  integrity sha512-BBruZFWmt3HFdVPS8kceTBIguKxu4f99n5JNp06OlPD/luoAMIaIK5ieV5YjnBLH3Nysai9sxj9rpJj4ZisXOA==
 
 cardinal@^2.1.1:
   version "2.1.1"

From d0a6fc4b8e1d58a29c92322d57c571e4b1efba0b Mon Sep 17 00:00:00 2001
From: Pierre de La Morinerie <kemenaran@gmail.com>
Date: Tue, 26 Oct 2021 12:34:11 +0000
Subject: [PATCH 6/9] ci: precompile (and cache) assets

This avoids the assets to be compiled lazily during the first spec,
which confuses test metrics.
---
 .github/workflows/ci.yml | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 468dad6dc..fe3ab76fe 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -90,5 +90,24 @@ jobs:
         run: |
           cp config/env.example .env
 
+      - name: Assets cache
+        uses: actions/cache@v2
+        with:
+          path: |
+            public/assets
+            public/packs-test
+            tmp/cache/webpacker
+          key: asset-cache-${{ runner.os }}-${{ github.ref }}-${{ github.sha }}
+          restore-keys: |
+            asset-cache-${{ runner.os }}-${{ github.ref }}-${{ github.sha }}
+            asset-cache-${{ runner.os }}-${{ github.ref }}-
+            asset-cache-${{ runner.os }}-
+
+      - name: Precompile assets
+        env:
+          RAILS_ENV: test
+        run: |
+          bin/rails assets:precompile --trace
+
       - name: Run tests
         run: ${{ matrix.pattern }}

From 641f0df712e006d4a2a36fc81344102a585528da Mon Sep 17 00:00:00 2001
From: Pierre de La Morinerie <kemenaran@gmail.com>
Date: Tue, 26 Oct 2021 14:35:18 +0200
Subject: [PATCH 7/9] ci: avoid installing node modules again

By default `bin/rails assets:precompile` will run `yarn install` again.

The suggested workaround is to remove `bin/yarn` before running the
task.

See https://github.com/rails/webpacker/issues/405
---
 .github/workflows/ci.yml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index fe3ab76fe..36cdbf541 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -107,6 +107,7 @@ jobs:
         env:
           RAILS_ENV: test
         run: |
+          rm bin/yarn
           bin/rails assets:precompile --trace
 
       - name: Run tests

From 184bf38bb293f50610d96d64e69b6407261120b9 Mon Sep 17 00:00:00 2001
From: Pierre de La Morinerie <kemenaran@gmail.com>
Date: Tue, 26 Oct 2021 14:58:48 +0000
Subject: [PATCH 8/9] ci: split actions into several sub-actions

---
 .github/actions/ci-setup-assets/action.yml |  26 ++++
 .github/actions/ci-setup-rails/action.yml  |  37 ++++++
 .github/workflows/ci.yml                   | 134 +++++++++------------
 3 files changed, 119 insertions(+), 78 deletions(-)
 create mode 100644 .github/actions/ci-setup-assets/action.yml
 create mode 100644 .github/actions/ci-setup-rails/action.yml

diff --git a/.github/actions/ci-setup-assets/action.yml b/.github/actions/ci-setup-assets/action.yml
new file mode 100644
index 000000000..6db13ed24
--- /dev/null
+++ b/.github/actions/ci-setup-assets/action.yml
@@ -0,0 +1,26 @@
+name: 'Setup Rails assets'
+description: 'Pre-compile and cache the app assets'
+
+runs:
+  using: composite
+  steps:
+    - name: Assets cache
+      uses: actions/cache@v2
+      with:
+        path: |
+          public/assets
+          public/packs-test
+          tmp/cache/webpacker
+        key: asset-cache-${{ runner.os }}-${{ github.ref }}-${{ github.sha }}
+        restore-keys: |
+          asset-cache-${{ runner.os }}-${{ github.ref }}-${{ github.sha }}
+          asset-cache-${{ runner.os }}-${{ github.ref }}-
+          asset-cache-${{ runner.os }}-
+
+    - name: Precompile assets
+      env:
+        RAILS_ENV: test
+      run: |
+        rm bin/yarn
+        bin/rails assets:precompile --trace
+      shell: bash
diff --git a/.github/actions/ci-setup-rails/action.yml b/.github/actions/ci-setup-rails/action.yml
new file mode 100644
index 000000000..76f431936
--- /dev/null
+++ b/.github/actions/ci-setup-rails/action.yml
@@ -0,0 +1,37 @@
+name: 'Setup Rails app'
+description: 'Setup the environment for running the Rails app'
+
+runs:
+  using: composite
+  steps:
+    - name: Setup Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        bundler-cache: true
+
+    - name: Setup Node
+      uses: actions/setup-node@v2
+      with:
+        node-version: '14'
+        cache: 'yarn'
+
+    - name: Install Node modules
+      run: yarn install --frozen-lockfile
+      shell: bash
+
+    - name: Setup environment variables
+      run: cp config/env.example .env
+      shell: bash
+
+    - name: Setup test database
+      env:
+        RAILS_ENV: test
+        DATABASE_URL: "postgres://tps_test@localhost:5432/tps_test"
+      run: bin/rails db:create db:schema:load db:migrate
+      shell: bash
+
+    - name: Setup split_tests binary
+      run: |
+        curl --no-progress-meter -L https://github.com/leonid-shevtsov/split_tests/releases/download/v0.3.0/split_tests.linux.gz | gunzip -c > split_tests
+        chmod +x split_tests
+      shell: bash
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 36cdbf541..849e52b22 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -9,30 +9,28 @@ jobs:
   linters:
     name: Linters
     runs-on: ubuntu-latest
+    services:
+      postgres:
+        image: postgres:12
+        env:
+          POSTGRES_USER: tps_test
+          POSTGRES_DB: tps_test
+          POSTGRES_PASSWORD: tps_test
+        ports: [ "5432:5432" ]
+
     steps:
-      - name: Checkout code
-        uses: actions/checkout@v2
+      - uses: actions/checkout@v2
 
-      - name: Setup Ruby
-        uses: ruby/setup-ruby@v1
-        with:
-          bundler-cache: true
-
-      - name: Setup Node
-        uses: actions/setup-node@v2
-        with:
-          node-version: '14'
-          cache: yarn
-
-      - name: Install node modules
-        run: yarn install --frozen-lockfile
+      - name: Setup the app code and dependancies
+        uses: ./.github/actions/ci-setup-rails
 
       - name: Run linters
         run: |
           bundle exec rake lint
+          bundle exec rake zeitwerk:check
 
-  tests:
-    name: Tests
+  unit_tests:
+    name: Unit tests
     runs-on: ubuntu-latest
     services:
       postgres:
@@ -45,70 +43,50 @@ jobs:
 
     strategy:
       matrix:
-        pattern:
-          - bin/rake zeitwerk:check
-          - bin/rspec $(./split_tests -line-count -glob='spec/**/*_spec.rb' -exclude-glob='spec/system/**' -split-index=0 -split-total=6)
-          - bin/rspec $(./split_tests -line-count -glob='spec/**/*_spec.rb' -exclude-glob='spec/system/**' -split-index=1 -split-total=6)
-          - bin/rspec $(./split_tests -line-count -glob='spec/**/*_spec.rb' -exclude-glob='spec/system/**' -split-index=2 -split-total=6)
-          - bin/rspec $(./split_tests -line-count -glob='spec/**/*_spec.rb' -exclude-glob='spec/system/**' -split-index=3 -split-total=6)
-          - bin/rspec $(./split_tests -line-count -glob='spec/**/*_spec.rb' -exclude-glob='spec/system/**' -split-index=4 -split-total=6)
-          - bin/rspec $(./split_tests -line-count -glob='spec/**/*_spec.rb' -exclude-glob='spec/system/**' -split-index=5 -split-total=6)
-          - bin/rspec $(./split_tests -line-count -glob='spec/system/**/*_spec.rb' -split-index=0 -split-total=2)
-          - bin/rspec $(./split_tests -line-count -glob='spec/system/**/*_spec.rb' -split-index=1 -split-total=2)
+        split_index: [0, 1, 2, 3, 4, 5]
 
     steps:
-      - name: Checkout code
-        uses: actions/checkout@v2
+      - uses: actions/checkout@v2
 
-      - name: Setup Ruby
-        uses: ruby/setup-ruby@v1
-        with:
-          bundler-cache: true
+      - name: Setup the app runtime and dependencies
+        uses: ./.github/actions/ci-setup-rails
 
-      - name: Setup Node
-        uses: actions/setup-node@v2
-        with:
-          node-version: '14'
-          cache: 'yarn'
-
-      - name: Install Node modules
-        run: yarn install --frozen-lockfile
-
-      - name: Setup split_tests binary
-        run: |
-          curl --no-progress-meter -L https://github.com/leonid-shevtsov/split_tests/releases/download/v0.3.0/split_tests.linux.gz | gunzip -c > split_tests
-          chmod +x split_tests
-
-      - name: Setup test database
-        env:
-          RAILS_ENV: test
-          DATABASE_URL: "postgres://tps_test@localhost:5432/tps_test"
-        run: |
-          bin/rails db:create db:schema:load db:migrate
-
-      - name: Setup environment variables
-        run: |
-          cp config/env.example .env
-
-      - name: Assets cache
-        uses: actions/cache@v2
-        with:
-          path: |
-            public/assets
-            public/packs-test
-            tmp/cache/webpacker
-          key: asset-cache-${{ runner.os }}-${{ github.ref }}-${{ github.sha }}
-          restore-keys: |
-            asset-cache-${{ runner.os }}-${{ github.ref }}-${{ github.sha }}
-            asset-cache-${{ runner.os }}-${{ github.ref }}-
-            asset-cache-${{ runner.os }}-
-
-      - name: Precompile assets
-        env:
-          RAILS_ENV: test
-        run: |
-          rm bin/yarn
-          bin/rails assets:precompile --trace
+      - name: Pre-compile assets
+        uses: ./.github/actions/ci-setup-assets
 
       - name: Run tests
-        run: ${{ matrix.pattern }}
+        run: |
+          SPEC_FILES=$(./split_tests -line-count -glob='spec/**/*_spec.rb' -exclude-glob='spec/system/**' -split-index=${{ matrix.split_index }} -split-total=6)
+          echo "Running tests for bin/rspec $SPEC_FILES"
+          bin/rspec $SPEC_FILES
+
+  system_tests:
+    name: System tests
+    runs-on: ubuntu-latest
+    services:
+      postgres:
+        image: postgres:12
+        env:
+          POSTGRES_USER: tps_test
+          POSTGRES_DB: tps_test
+          POSTGRES_PASSWORD: tps_test
+        ports: ["5432:5432"]
+
+    strategy:
+      matrix:
+        split_index: [0, 1]
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Setup the app runtime and dependencies
+        uses: ./.github/actions/ci-setup-rails
+
+      - name: Pre-compile assets
+        uses: ./.github/actions/ci-setup-assets
+
+      - name: Run tests
+        run: |
+          SPEC_FILES=$(./split_tests -line-count -glob='spec/system/**/*_spec.rb' -split-index=${{ matrix.split_index }} -split-total=2)
+          echo "Running tests for bin/rspec $SPEC_FILES"
+          bin/rspec $SPEC_FILES

From 75e207122b5aa3c3de4b73efddcf5d5bc6e7243e Mon Sep 17 00:00:00 2001
From: Pierre de La Morinerie <kemenaran@gmail.com>
Date: Wed, 3 Nov 2021 20:54:54 +0000
Subject: [PATCH 9/9] ci: use previous test timings to split the tests

---
 .../actions/ci-save-split-tests/action.yml    | 17 ++++++
 .github/actions/ci-setup-rails/action.yml     |  6 ---
 .../actions/ci-setup-split-tests/action.yml   | 46 ++++++++++++++++
 .github/workflows/ci.yml                      | 53 ++++++++++++++++---
 Gemfile                                       |  1 +
 Gemfile.lock                                  |  3 ++
 6 files changed, 114 insertions(+), 12 deletions(-)
 create mode 100644 .github/actions/ci-save-split-tests/action.yml
 create mode 100644 .github/actions/ci-setup-split-tests/action.yml

diff --git a/.github/actions/ci-save-split-tests/action.yml b/.github/actions/ci-save-split-tests/action.yml
new file mode 100644
index 000000000..2f9e8896f
--- /dev/null
+++ b/.github/actions/ci-save-split-tests/action.yml
@@ -0,0 +1,17 @@
+name: 'Save split-tests'
+description: 'Save Junit test results and timing data, to better split future tests'
+
+inputs:
+  results_path:
+    description: 'Glob pattern to the JUnit files to save'
+    required: true
+
+# This should be run once the results from all runs are collected.
+runs:
+  using: composite
+  steps:
+    - name: Save test reports
+      uses: actions/cache@v2
+      with:
+        path: ${{ inputs.results_path }}
+        key: tests-reports-${{ github.ref }}-${{ github.sha }}-${{ github.run_id }}
diff --git a/.github/actions/ci-setup-rails/action.yml b/.github/actions/ci-setup-rails/action.yml
index 76f431936..7f4b9edb8 100644
--- a/.github/actions/ci-setup-rails/action.yml
+++ b/.github/actions/ci-setup-rails/action.yml
@@ -29,9 +29,3 @@ runs:
         DATABASE_URL: "postgres://tps_test@localhost:5432/tps_test"
       run: bin/rails db:create db:schema:load db:migrate
       shell: bash
-
-    - name: Setup split_tests binary
-      run: |
-        curl --no-progress-meter -L https://github.com/leonid-shevtsov/split_tests/releases/download/v0.3.0/split_tests.linux.gz | gunzip -c > split_tests
-        chmod +x split_tests
-      shell: bash
diff --git a/.github/actions/ci-setup-split-tests/action.yml b/.github/actions/ci-setup-split-tests/action.yml
new file mode 100644
index 000000000..e49f4c2f4
--- /dev/null
+++ b/.github/actions/ci-setup-split-tests/action.yml
@@ -0,0 +1,46 @@
+name: 'Setup split-tests'
+description: 'Setup the environment for splitting tests'
+
+inputs:
+  results_path:
+    description: 'Glob pattern to the JUnit files to save'
+    required: true
+
+runs:
+  using: composite
+  steps:
+    - name: Setup split_tests binary
+      run: |
+        curl --no-progress-meter -L https://github.com/leonid-shevtsov/split_tests/releases/download/v0.3.0/split_tests.linux.gz | gunzip -c > split_tests
+        chmod +x split_tests
+      shell: bash
+
+    - name: Generate an unique random value
+      run: echo dummy_random_value=$RANDOM >> $GITHUB_ENV
+      shell: bash
+
+    # Restore previous runs timing from the cache.
+    #
+    # NB: at the end of the job, the `actions/cache@v2` action will attempt
+    # to save the results back to the same key. However at this stage only
+    # tests results for a single instance will be available.
+    #
+    # To avoid the cache being overwritten with this single result, we define
+    # a random cache key, which the action will use to save the single-instance
+    # report to a dummy location.
+    #
+    # The actual retrieval uses the `restore-keys` instead.
+    - name: Restore previous runs timings
+      uses: actions/cache@v2
+      with:
+        path: ${{ inputs.results_path }}
+        key: single-instance-report-${{ github.sha }}-${{ env.dummy_random_value }}
+        restore-keys: |
+          tests-reports-${{ github.ref }}-${{ github.sha }}-${{ github.run_id }}
+          tests-reports-${{ github.ref }}-${{ github.sha }}-
+          tests-reports-${{ github.ref }}-
+          tests-reports-
+
+    - name: Display previous runs timings used for splitting tests
+      run: ls ${{ inputs.results_path }} || true
+      shell: bash
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 849e52b22..4c177b4ce 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -43,7 +43,7 @@ jobs:
 
     strategy:
       matrix:
-        split_index: [0, 1, 2, 3, 4, 5]
+        instances: [0, 1, 2, 3, 4, 5]
 
     steps:
       - uses: actions/checkout@v2
@@ -54,11 +54,22 @@ jobs:
       - name: Pre-compile assets
         uses: ./.github/actions/ci-setup-assets
 
+      - name: Setup split tests
+        uses: ./.github/actions/ci-setup-split-tests
+        with:
+          results_path: tmp/*.junit.xml
+
       - name: Run tests
         run: |
-          SPEC_FILES=$(./split_tests -line-count -glob='spec/**/*_spec.rb' -exclude-glob='spec/system/**' -split-index=${{ matrix.split_index }} -split-total=6)
+          SPEC_FILES=$(./split_tests -glob='spec/**/*_spec.rb' -exclude-glob='spec/system/**' -split-index=${{ strategy.job-index }} -split-total=${{ strategy.job-total }} -junit -junit-path=tmp/*.junit.xml)
           echo "Running tests for bin/rspec $SPEC_FILES"
-          bin/rspec $SPEC_FILES
+          bin/rspec $SPEC_FILES --format progress --format RspecJunitFormatter --out tmp/rspec_${{ github.job }}_${{ strategy.job-index }}.junit.xml
+
+      - name: Upload test results for this instance
+        uses: actions/upload-artifact@v2
+        with:
+          name: test-reports
+          path: tmp/rspec_${{ github.job }}_${{ strategy.job-index }}.junit.xml
 
   system_tests:
     name: System tests
@@ -74,7 +85,7 @@ jobs:
 
     strategy:
       matrix:
-        split_index: [0, 1]
+        instances: [0, 1]
 
     steps:
       - uses: actions/checkout@v2
@@ -85,8 +96,38 @@ jobs:
       - name: Pre-compile assets
         uses: ./.github/actions/ci-setup-assets
 
+      - name: Setup split tests
+        uses: ./.github/actions/ci-setup-split-tests
+        with:
+          results_path: tmp/*.junit.xml
+
       - name: Run tests
         run: |
-          SPEC_FILES=$(./split_tests -line-count -glob='spec/system/**/*_spec.rb' -split-index=${{ matrix.split_index }} -split-total=2)
+          SPEC_FILES=$(./split_tests -glob='spec/system/**/*_spec.rb' -split-index=${{ strategy.job-index }} -split-total=${{ strategy.job-total }} -junit -junit-path=tmp/*.junit.xml)
           echo "Running tests for bin/rspec $SPEC_FILES"
-          bin/rspec $SPEC_FILES
+          bin/rspec $SPEC_FILES --format progress --format RspecJunitFormatter --out tmp/rspec_${{ github.job }}_${{ strategy.job-index }}.junit.xml
+
+      - name: Upload test results for this instance
+        uses: actions/upload-artifact@v2
+        with:
+          name: test-reports
+          path: tmp/rspec_${{ github.job }}_${{ strategy.job-index }}.junit.xml
+
+  save_test_reports:
+    name: Save test reports
+    needs: [unit_tests, system_tests]
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Collect test results from all instances
+        uses: actions/download-artifact@v2
+        with:
+          name: test-reports
+          path: tmp
+
+      - name: Save test results and timing data, to better split future tests
+        uses: ./.github/actions/ci-save-split-tests
+        with:
+          results_path: tmp/*.junit.xml
diff --git a/Gemfile b/Gemfile
index 5fbc1aa53..0890ef679 100644
--- a/Gemfile
+++ b/Gemfile
@@ -92,6 +92,7 @@ group :test do
   gem 'factory_bot'
   gem 'launchy'
   gem 'rails-controller-testing'
+  gem 'rspec_junit_formatter'
   gem 'selenium-webdriver'
   gem 'shoulda-matchers', require: false
   gem 'timecop'
diff --git a/Gemfile.lock b/Gemfile.lock
index 0e778a197..913c4f27a 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -596,6 +596,8 @@ GEM
       rspec-mocks (~> 3.10)
       rspec-support (~> 3.10)
     rspec-support (3.10.2)
+    rspec_junit_formatter (0.4.1)
+      rspec-core (>= 2, < 4, != 2.12.0)
     rubocop (1.10.0)
       parallel (~> 1.10)
       parser (>= 3.0.0.0)
@@ -856,6 +858,7 @@ DEPENDENCIES
   rgeo-geojson
   rqrcode
   rspec-rails
+  rspec_junit_formatter
   rubocop
   rubocop-rails_config
   rubocop-rspec-focused