From db7e14a8ea50f5cb3ec1bbe73a108d5d03e57716 Mon Sep 17 00:00:00 2001
From: Isaac Good <github@isaacgood.com>
Date: Mon, 4 May 2026 18:11:47 -0700
Subject: [PATCH 1/2] Switch the test runner Docker image to use Alpine.

This shrinks the image from 244MB to 14.6MB.

78MB of the prior image is the Ubuntu layer so we don't actually reclaim
that space. However, the Ubuntu `apt-get` command adds 166MB vs the
Alpine `apk add` which adds 5.6MB. That saves 160MB.

This passes all the tests and example solutions once
https://github.com/exercism/bash/pull/771 and
https://github.com/exercism/bash/pull/772 are included.
---
 Dockerfile | 34 ++++++++++++++++++----------------
 bin/run.sh |  3 ++-
 2 files changed, 20 insertions(+), 17 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index f1d2a6b..af683d8 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,22 +1,24 @@
-FROM ubuntu:24.04
+# To refresh, copy the Digest from
+# docker image inspect alpine:3.23.4 | jq -r '.[0].Id'
+FROM alpine@sha256:5b10f432ef3da1b8d4c7eb6c487f2f5a8f096bc91145e68878dd4a5019afde11
 
-# Ubuntu 24.04 ships with bash version 5.2
-# https://hub.docker.com/layers/library/ubuntu/24.04/images/sha256-3963c438d67a34318a3672faa6debd1dfff48e5d52de54305988b932c61514ca?context=explore
-# 24.04 provides bats v1.10.0
-# Test runner needs jq.
-# Other commands to add to environment, might be used by students
-#   - bc
-#   - GNU awk (Ubuntu 20.04 ships with mawk)
-# Tools commonly used by students that will already be installed include:
-#   - sed, tr, ...
-
-RUN apt-get update                      && \
-    apt-get install -y bats jq bc gawk  && \
-    apt-get purge --auto-remove -y      && \
-    apt-get clean                       && \
-    rm -rf /var/lib/apt/lists/*
+# bats: the test runner framework
+# bash: the language
+# bc:   used for float arithmetic
+# coreutils: provides GNU version of tools like `date`
+# gawk: used for float arithmetic
+# jq:   used for JSON
+RUN apk add --no-cache bats bash bc coreutils gawk jq
 
 COPY . /opt/test-runner
 WORKDIR /opt/test-runner
 ENV BATS_RUN_SKIPPED=true
 ENTRYPOINT ["/opt/test-runner/bin/run.sh"]
+
+# $ docker build --rm -t exercism/bash-test-runner .
+# $ docker run -it --entrypoint bash exercism/bash-test-runner -c 'for i in awk bash bats bc jq; do "$i" --version | head -n1; done'
+# GNU Awk 5.3.2, API 4.0
+# GNU bash, version 5.3.3(1)-release (x86_64-alpine-linux-musl)
+# Bats 1.13.0
+# bc 1.08.2
+# jq-1.8.1
diff --git a/bin/run.sh b/bin/run.sh
index 517047a..fe1dde2 100755
--- a/bin/run.sh
+++ b/bin/run.sh
@@ -69,7 +69,8 @@ run_tests() {
         [[ -f "$test_file" ]] || test_file="${slug//-/_}_test.sh"
     fi
 
-    perl -i -pe 's/(load bats-extra)\.bash/$1/' "$test_file"
+    contents=$( < "$test_file" )
+    sed 's/(load bats-extra)\.bash/$1/' > "$test_file" <<< "$contents"
 
     echo "Test output:"
 

From a8701d05e26f6b49d7f796a3d18448dddd2bdab4 Mon Sep 17 00:00:00 2001
From: Isaac Good <github@isaacgood.com>
Date: Mon, 4 May 2026 18:33:51 -0700
Subject: [PATCH 2/2] Do not create a test file where none previously existed

---
 bin/run.sh | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/bin/run.sh b/bin/run.sh
index fe1dde2..18a6171 100755
--- a/bin/run.sh
+++ b/bin/run.sh
@@ -69,8 +69,10 @@ run_tests() {
         [[ -f "$test_file" ]] || test_file="${slug//-/_}_test.sh"
     fi
 
-    contents=$( < "$test_file" )
-    sed 's/(load bats-extra)\.bash/$1/' > "$test_file" <<< "$contents"
+    if [[ -e "$test_file" ]]; then
+        contents=$( < "$test_file" )
+        sed 's/(load bats-extra)\.bash/$1/' > "$test_file" <<< "$contents"
+    fi
 
     echo "Test output:"