test-packaging.yaml: Add step "Build in repository"

Run "make all" in the repository source before packaging and tests.
That's the state in-repo tests should find before running, and
indeed, as of now some in-repo tests don't run correctly due to
missing __init__py files generated during build.

Signed-off-by: Jan Lindemann <jan@janware.com>

.github/workflows/test-packaging.yaml

@@ -54,6 +54,12 @@ jobs:
           set -euxo pipefail
           make -C "${{ github.event.repository.name }}" check
 
+      - name: Build in repository source
+        shell: bash
+        run: |
+          set -euxo pipefail
+          make -C "${{ github.event.repository.name }}" all
+
       - name: Build package
         shell: bash
         run: |
@@ -66,7 +72,7 @@ jobs:
           set -euxo pipefail
           make -C "${{ github.event.repository.name }}" check
 
-      - name: Run post-build integration tests against repo
+      - name: Run unit + integration tests against repository
         shell: bash
         run: |
           set -euxo pipefail