diff --git a/.github/actions/run-tests/action.yml b/.github/actions/run-tests/action.yml
new file mode 100644
index 0000000..6f3b20c
--- /dev/null
+++ b/.github/actions/run-tests/action.yml
@@ -0,0 +1,19 @@
+name: "Run tests"
+description: "Install fish and Oh My Fish! if necessary and run CI tests"
+runs:
+  using: "composite"
+  steps:
+    - name: Install Fish
+      shell: bash
+      if: runner.os == 'macOS'
+      run: brew update && brew install fish
+
+    - name: Install Oh My Fish!
+      shell: bash
+      run: fish bin/install --verbose --offline --noninteractive --yes
+
+    - name: Run tests on latest fish
+      shell: bash
+      run: |
+        tests/run.fish
+        fish -c 'fish-spec pkg/{fish-spec,omf}/spec/*_spec.fish'
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index eca9544..53ef3e8 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -7,50 +7,45 @@ on:
     paths-ignore:
       - '**.md'
 jobs:
-  build:
+  build-linux:
+    strategy:
+      fail-fast: false
+      matrix:
+        # only use the latest patch level for all minor versions to reduce number of jobs
+        fish:
+          - '3.0.0' # since 3.0.0 is the oldest officially supported version it's included as well
+          - '3.0.2'
+          - '3.1.2'
+          - '3.2.2'
+          - '3.3.1'
+          - '3.4.1'
+          - '3.5.1'
+          - '3.6.4'
+          - '3.7.1'
+          - '4.0.0'
+    runs-on: ubuntu-latest
+    container:
+      image: ohmyfish/fish:${{ matrix.fish }}
+      options: --user root
+    steps:
+      - name: Checkout the repository
+        uses: actions/checkout@v4
+
+      - name: Run tests
+        uses: ./.github/actions/run-tests
+
+  build-macos:
     strategy:
       fail-fast: false
       matrix:
         os:
-          - ubuntu-20.04
-          - ubuntu-22.04
-          - ubuntu-latest
-        fish:
-          - stock
-          - 3
-          - 4
-          - brew
-        exclude:
-          - os: ubuntu-20.04
-            fish: 4
-          - os: ubuntu-latest
-            fish: 4
-        include:
-          - os: macos-latest
-            fish: brew
-          - os: macos-13
-            fish: brew
-          - os: macos-14
-            fish: brew
+          - macos-latest
+          - macos-13
+          - macos-14
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout the repository
-        uses: actions/checkout@v3
-
-      - name: Add brew to path for Ubuntu
-        if: startsWith(matrix.os, 'ubuntu') && matrix.fish == 'brew'
-        run: |
-          echo "/home/linuxbrew/.linuxbrew/bin" >> $GITHUB_PATH
-          echo "/home/linuxbrew/.linuxbrew/sbin" >> $GITHUB_PATH
-
-      - name: Install Fish
-        run: FISH_RELEASE=${{ matrix.fish }} tools/ci-install-fish.sh
-
-      - name: Install Oh My Fish!
-        run: fish bin/install --verbose --offline --noninteractive --yes
+        uses: actions/checkout@v4
 
       - name: Run tests
-        run: |
-          tests/run.fish
-          pushd pkg/fish-spec; fish -c 'fish-spec'; popd
-          pushd pkg/omf; fish -c 'fish-spec'; popd
+        uses: ./.github/actions/run-tests
diff --git a/pkg/fish-spec/functions/fish-spec.fish b/pkg/fish-spec/functions/fish-spec.fish
index 8599e60..6c1cdd8 100644
--- a/pkg/fish-spec/functions/fish-spec.fish
+++ b/pkg/fish-spec/functions/fish-spec.fish
@@ -75,29 +75,32 @@ function __fish_spec_run_test_function -a test_func
   set test_func_human_readable (string replace 'it_' 'IT ' $test_func | string replace -a '_' ' ')
   __fish_spec.color.echo-n.info "⏳ $test_func_human_readable"
 
+  set -l before_each_output ""
   if functions --query before_each
-    set -l before_each_output (before_each 2>&1 | string collect)
+    before_each 2>1 | while read -l line; test -z "$before_each_output" && set before_each_output $line || set before_each_output $before_each_output\n$line; end
   end
 
-  set -l test_func_output ($test_func 2>&1 | string collect)
+  set -l test_func_output ""
+  $test_func 2>&1 | while read -l line; test -z "$test_func_output" && set test_func_output $line || set test_func_output $test_func_output\n$line; end
   set result $status
 
+  set -l after_each_output ""
   if functions --query after_each
-    set -l before_each_output (before_each 2>&1 | string collect)
+    after_each 2>&1 | while read -l line; test -z "$after_each_output" && set after_each_output $line || set after_each_output $after_each_output\n$line; end
   end
 
   if test $__fish_spec_last_assertion_failed = no
     __fish_spec.color.echo.success \r"✅ $test_func_human_readable passed!"
     if test "$FISH_SPEC_VERBOSE" = 1
-      test -n "$before_each_output" && echo $before_each_output
-      test -n "$test_func_output" && echo $test_func_output
-      test -n "$after_each_output" && echo $after_each_output
+      test -n "$before_each_output" && echo "$before_each_output"
+      test -n "$test_func_output" && echo "$test_func_output"
+      test -n "$after_each_output" && echo "$after_each_output"
     end
   else
     __fish_spec.color.echo.failure \r"❌ $test_func_human_readable failed."
-    test -n "$before_each_output" && echo $before_each_output
-    test -n "$test_func_output" && echo $test_func_output
-    test -n "$after_each_output" && echo $after_each_output
+    test -n "$before_each_output" && echo "$before_each_output"
+    test -n "$test_func_output" && echo "$test_func_output"
+    test -n "$after_each_output" && echo "$after_each_output"
     set __fish_spec_last_assertion_failed no
   end
 end
diff --git a/tools/ci-install-fish.sh b/tools/ci-install-fish.sh
deleted file mode 100755
index dc0164a..0000000
--- a/tools/ci-install-fish.sh
+++ /dev/null
@@ -1,26 +0,0 @@
-#!/usr/bin/env bash
-
-set -o pipefail
-set -o errexit
-set -o nounset
-
-if [[ $FISH_RELEASE = "brew" ]]; then
-  brew update
-  brew install fish
-else
-  if [[ $FISH_RELEASE == "4" ]]; then
-    REPO_PPA="ppa:fish-shell/beta-4"
-  else
-    REPO_PPA="ppa:fish-shell/release-3"
-  fi
-
-  if [[ $FISH_RELEASE != "stock" ]]; then
-    sudo apt-add-repository -y $REPO_PPA
-  fi
-
-  sudo apt-cache policy fish
-  sudo apt-get update
-  sudo apt-get install -y fish
-fi
-
-fish --version