.github: run unit tests with -DBUILD_UNIT_TESTS_HOST=ON

Because we can.

Signed-off-by: Marc Herbert <marc.herbert@intel.com>

.github/workflows/unit-tests.yml

@@ -0,0 +1,21 @@
+---
+
+# https://thesofproject.github.io/latest/developer_guides/unit_tests.html
+
+name: Unit tests
+
+# 'workflow_dispatch' allows running this workflow manually from the
+# 'Actions' tab
+
+# yamllint disable-line rule:truthy
+on: [pull_request, workflow_dispatch]
+
+jobs:
+  cmocka_utests:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with: {fetch-depth: 2}
+
+      - name: build and run all defconfigs
+        run: ./test/test-all-defconfigs.sh

test/test-all-defconfigs.sh

@@ -0,0 +1,39 @@
+#!/bin/sh
+
+set -e
+
+SOFTOP=$(cd "$(dirname "$0")"/.. && pwd)
+
+BUILDTOP=build_ut_defs
+
+rebuild_config()
+{
+    local conf="$1"
+    mkdir -p "$BUILDTOP"
+    ( set -x
+     cmake  -DINIT_CONFIG="$conf" -B "$BUILDTOP"/"$conf" -DBUILD_UNIT_TESTS=ON \
+           -DBUILD_UNIT_TESTS_HOST=ON
+
+     cmake --build "$BUILDTOP"/"$conf" -- -j"$(nproc)"
+    )
+}
+
+main()
+{
+    local defconfig
+
+    # First make sure all configurations build
+    for d in "$SOFTOP"/src/arch/xtensa/configs/*_defconfig; do
+        defconfig=$(basename "$d")
+        rebuild_config "$defconfig"
+    done
+
+    # Now run all the tests
+    for d in "$BUILDTOP"/*_defconfig; do
+        ( set -x
+         cmake --build "$d" -- test
+        )
+    done
+}
+
+main "$@"