Run ImageTestSuite in CI

Author: treeform

.github/workflows/build.yml

@@ -14,6 +14,9 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v5
+      - name: Clone ImageTestSuite
+        shell: bash
+        run: git clone --depth 1 https://github.com/treeform/imagetestsuite ../imagetestsuite
       - uses: treeform/setup-nim-action@v6
       - name: Install dependencies
         shell: bash
@@ -22,3 +25,4 @@ jobs:
           nimby install -g pixie/pixie.nimble
       - run: nim r tests/tests.nim
       - run: nim cpp -r tests/tests.nim
+      - run: nim r tests/imagetestsuite.nim