diff --git a/.github/workflows/testing.yml b/.github/workflows/testing.yml
index bed596dc..a7438326 100644
--- a/.github/workflows/testing.yml
+++ b/.github/workflows/testing.yml
@@ -55,6 +55,17 @@ jobs:
         with:
           name: rgbds-canary-${{ matrix.os }}-${{ matrix.cc }}-${{ matrix.buildsys }}
           path: bins
+      - name: Check test dependency repositories cache
+        id: test-deps-cache
+        uses: actions/cache@v3
+        with:
+          path: test
+          key: ${{ hashFiles('test/fetch-test-deps.sh') }}
+      - if: ${{ steps.test-deps-cache.outputs.cache-hit != 'true' }}
+        name: Fetch test dependency repositories
+        continue-on-error: true
+        run: |
+          test/fetch-test-deps.sh
       - name: Test
         shell: bash
         run: |
@@ -116,6 +127,18 @@ jobs:
         with:
           name: rgbds-canary-win${{ matrix.bits }}
           path: bins
+      - name: Check test dependency repositories cache
+        id: test-deps-cache
+        uses: actions/cache@v3
+        with:
+          path: test
+          key: ${{ hashFiles('test/fetch-test-deps.sh') }}
+      - if: ${{ steps.test-deps-cache.outputs.cache-hit != 'true' }}
+        name: Fetch test dependency repositories
+        shell: bash
+        continue-on-error: true
+        run: |
+          test/fetch-test-deps.sh
       - name: Test
         shell: bash
         run: |
@@ -198,6 +221,18 @@ jobs:
         run: |
           cp bins/* .
           cp bins/*.dll test/gfx
+      - name: Check test dependency repositories cache
+        id: test-deps-cache
+        uses: actions/cache@v3
+        with:
+          path: test
+          key: ${{ hashFiles('test/fetch-test-deps.sh') }}
+      - if: ${{ steps.test-deps-cache.outputs.cache-hit != 'true' }}
+        name: Fetch test dependency repositories
+        shell: bash
+        continue-on-error: true
+        run: |
+          test/fetch-test-deps.sh
       - name: Run tests
         shell: bash
         run: |
diff --git a/test/fetch-test-deps.sh b/test/fetch-test-deps.sh
new file mode 100755
index 00000000..0025d85a
--- /dev/null
+++ b/test/fetch-test-deps.sh
@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+
+set -e
+
+cd "$(dirname "$0")"
+
+echo "Fetching test dependency repositories"
+
+fetch_downstream() { # owner/repo shallow-since commit
+	if [ ! -d ${1##*/} ]; then
+		git clone https://github.com/$1.git --shallow-since=$2 --single-branch
+	fi
+	pushd ${1##*/}
+	git checkout -f $3
+	if [ -f ../patches/${1##*/}.patch ]; then
+		git apply --ignore-whitespace ../patches/${1##*/}.patch
+	fi
+	popd
+}
+
+fetch_downstream pret/pokecrystal 2022-09-29 70a3ec1accb6de1c1c273470af0ddfa2edc1b0a9
+fetch_downstream pret/pokered     2022-09-29 2b52ceb718b55dce038db24d177715ae4281d065
+fetch_downstream AntonioND/ucity  2022-04-20 d8878233da7a6569f09f87b144cb5bf140146a0f
diff --git a/test/run-tests.sh b/test/run-tests.sh
index a969eadc..79eb3221 100755
--- a/test/run-tests.sh
+++ b/test/run-tests.sh
@@ -25,20 +25,16 @@ done
 # When updating subprojects, change the commit being checked out, and set the `shallow-since`
 # to the day before, to reduce the amount of refs being transferred and thus speed up CI.
 
-test_downstream() { # owner/repo shallow-since commit make-target
-	if [ ! -d ${1##*/} ]; then
-		git clone https://github.com/$1.git --shallow-since=$2 --single-branch
-	fi
-	pushd ${1##*/}
-	git checkout -f $3
-	if [ -f ../patches/${1##*/}.patch ]; then
-		git apply --ignore-whitespace ../patches/${1##*/}.patch
+test_downstream() { # owner/repo make-target
+	if ! pushd ${1##*/}; then
+		echo >&2 'Please run `fetch-test-deps.sh` before running the test suite'
+		return 1
 	fi
 	make clean
-	make -j4 $4 RGBDS=../../
+	make -j4 $2 RGBDS=../../
 	popd
 }
 
-test_downstream pret/pokecrystal 2022-09-29 70a3ec1accb6de1c1c273470af0ddfa2edc1b0a9 compare
-test_downstream pret/pokered     2022-09-29 2b52ceb718b55dce038db24d177715ae4281d065 compare
-test_downstream AntonioND/ucity  2022-04-20 d8878233da7a6569f09f87b144cb5bf140146a0f ''
+test_downstream pret/pokecrystal compare
+test_downstream pret/pokered     compare
+test_downstream AntonioND/ucity  ''