Added infrastructure for automatic tests

app/build.gradle

@@ -117,6 +117,8 @@ dependencies {
     def dnsjava_version = "2.1.8"
     def openpgp_version = "12.0"
     def requery_version = "3.26.0"
+    def junit_version = "5.3.1"
+    def assertj_version = "3.11.1"
 
     // https://developer.android.com/jetpack/docs/release-notes
 
@@ -178,4 +180,11 @@ dependencies {
 
     // git clone https://android.googlesource.com/platform/frameworks/opt/colorpicker
     implementation project(path: ':colorpicker')
+
+    // https://junit.org/junit5/
+    testImplementation "org.junit.jupiter:junit-jupiter-api:$junit_version"
+    testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:$junit_version"
+
+    // https://joel-costigliola.github.io/assertj/
+    testImplementation "org.assertj:assertj-core:$assertj_version"
 }