ci: Remove duplicated steps for running tests

The environment variable FEATURES sets the set of features used
while testing, that makes it possible to have just one step
and prevent code duplication.

.github/workflows/test_rust.yml

@@ -10,6 +10,9 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
+env:
+  FEATURES: lzma,jpegxr
+
 jobs:
   changes:
     name: Paths filter
@@ -67,6 +70,11 @@ jobs:
         if: runner.os == 'Linux'
         run: echo RUSTFLAGS=${RUSTFLAGS}\ --cfg=web_sys_unstable_apis\ -Clink-args=-znostart-stop-gc >> $GITHUB_ENV
 
+      - name: Enable image tests
+        if: runner.os != 'macOS'
+        shell: bash
+        run: echo FEATURES=${FEATURES},imgtests | tee -a $GITHUB_ENV
+
       - name: Cache Cargo output
         uses: Swatinem/rust-cache@v2
         with:
@@ -78,9 +86,9 @@ jobs:
         with:
           tool: cargo-nextest
 
-      - name: Run tests with image tests
-        if: runner.os != 'macOS'
-        run: cargo nextest run --profile ci --cargo-profile ci --workspace --locked --no-fail-fast -j 4 --features imgtests,lzma,jpegxr
+      - name: Run tests
+        shell: bash
+        run: cargo nextest run --profile ci --cargo-profile ci --workspace --locked --no-fail-fast -j 4 --features ${FEATURES}
         env:
           # This is to counteract the disabling by rust-cache.
           # See: https://github.com/Swatinem/rust-cache/issues/43
@@ -93,12 +101,6 @@ jobs:
           RUSTUP_WINDOWS_PATH_ADD_BIN: '1'
           XDG_RUNTIME_DIR: '' # dummy value, just to silence warnings about it missing
 
-      - name: Run tests without image tests
-        if: runner.os == 'macOS'
-        run: cargo nextest run --profile ci --cargo-profile ci --workspace --locked --no-fail-fast -j 4 --features lzma,jpegxr
-        env:
-          XDG_RUNTIME_DIR: '' # dummy value, just to silence warnings about it missing
-
       - name: Upload images
         if: failure()
         uses: actions/upload-artifact@v4