(ci) Add tests for Sonatype repo configuration

Author: swallez

java-client/build.gradle.kts

@@ -140,8 +140,14 @@ publishing {
             name = "MavenCentralSnapshot"
             url = uri("https://s01.oss.sonatype.org/content/repositories/snapshots/")
             credentials {
-                username = providers.gradleProperty("ossrhUsername").get()
-                password = providers.gradleProperty("ossrhPassword").get()
+                run {
+                    if (gradle.startParameter.taskNames.find { it.contains("ToMavenCentralSnapshotRepository") } != null) {
+                        if (!providers.gradleProperty("ossrhUsername").isPresent) logger.error("ossrhUsername not set")
+                        if (!providers.gradleProperty("ossrhPassword").isPresent) logger.error("ossrhPassword not set")
+                    }
+                }
+                username = providers.gradleProperty("ossrhUsername").orNull
+                password = providers.gradleProperty("ossrhPassword").orNull
             }
         }
     }