test: build local spread binary

Don't rely on GitHub runners providing a (potentially outdated)
spread binary. Instead, check out a reference version and build a
local binary to be used in the github CI test.

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

Author: cmatsuoka

.github/workflows/test.yaml

@@ -11,13 +11,33 @@ on:
 
 jobs:
   run-tests:
-    runs-on: self-hosted
+    #runs-on: [self-hosted, spread-enabled]
+    runs-on: [self-hosted]
     steps:
       - uses: actions/checkout@v4
 
-      - name: Run tests
+      - name: Run unit tests
         run: |
-          spread google:
+          sudo snap install go --classic
+          go test -v ./...
+
+      - name: Build local spread
+        run: |
+          mkdir spread-testing
+          cd spread-testing
+          git init
+          git remote add origin https://github.com/canonical/spread.git
+          git fetch --depth=1 origin ae284792596e00d325a1787604fe4ec7e00574aa
+          git checkout FETCH_HEAD
+          go build -o spread-testing ./cmd/spread
+          sudo cp spread-testing /usr/bin/spread
+
+      - name: Run spread tests
+        run: |
+          trap "rm -f secret.txt" EXIT
+          echo "${{ secrets.SPREAD_GOOGLE_KEY }}" > .secret.txt
+          /usr/bin/spread google:
+        env:
 
       - name: Discard spread workers
         if: always()

spread.yaml

@@ -16,7 +16,7 @@ environment:
 
 backends:
     google:
-        key: "$(HOST: echo $SPREAD_GOOGLE_KEY)"
+        key: "$(HOST: cat .secret.txt)"
         location: snapd-spread/us-east1-b
         halt-timeout: 2h
         systems: