test: extract build.gradle to a file in __tests__ dir

.github/workflows/e2e-cache.yml

@@ -33,17 +33,7 @@ jobs:
           cache: gradle
       - name: Create files to cache
         run: |
-          cat <<EOF > build.gradle
+          cp __tests__/cache/gradle/build.gradle .
-            plugins { id 'java' }
-            repositories { mavenCentral() }
-            dependencies { implementation 'org.codehaus.groovy:groovy:1.8.6' }
-            tasks.register('downloadDependencies') { doLast {
-              def total = configurations.compileClasspath.inject (0) { sum, file ->
-                sum + file.length()
-              }
-              println total
-            }}
-          EOF
           gradle downloadDependencies
           if [ ! -d ~/.gradle/caches ]; then
             echo "::error::The ~/.gradle/caches directory does not exist unexpectedly"
@@ -57,17 +47,7 @@ jobs:
         uses: actions/checkout@v2
       - name: Create build.gradle
         run: |
-          cat <<EOF > build.gradle
+          cp __tests__/cache/gradle/build.gradle .
-            plugins { id 'java' }
-            repositories { mavenCentral() }
-            dependencies { implementation 'org.codehaus.groovy:groovy:1.8.6' }
-            tasks.register('downloadDependencies') { doLast {
-              def total = configurations.compileClasspath.inject (0) { sum, file ->
-                sum + file.length()
-              }
-              println total
-            }}
-          EOF
           if [ -d ~/.gradle/caches ]; then
             echo "::error::The ~/.gradle/caches directory exists unexpectedly"
             exit 1

__tests__/cache/gradle/build.gradle

@@ -0,0 +1,17 @@
+plugins {
+    id 'java'
+}
+repositories {
+    mavenCentral()
+}
+dependencies {
+    implementation 'org.codehaus.groovy:groovy:1.8.6'
+}
+tasks.register('downloadDependencies') {
+    doLast {
+        def total = configurations.compileClasspath.inject (0) { sum, file ->
+            sum + file.length()
+        }
+        println total
+    }
+}