DependencyRuleTest.kt

package com.github.philipjkim.demo.hexagonal

import ch.qos.logback.classic.Level
import ch.qos.logback.classic.Logger
import com.tngtech.archunit.core.importer.ClassFileImporter
import com.tngtech.archunit.lang.syntax.ArchRuleDefinition.noClasses
import org.junit.jupiter.api.Assertions.*
import org.junit.jupiter.api.BeforeAll
import org.junit.jupiter.api.DisplayName
import org.junit.jupiter.api.Nested
import org.junit.jupiter.api.Test
import org.slf4j.LoggerFactory

/*
 * Layer dependency direction:
 * external -> adapter -> application -> domain
 */
@DisplayName("package dependency rule")
internal class DependencyRuleTest {

  @Nested
  @DisplayName("for callback domain")
  inner class ForCallbackDomain {
    private val basePackage = "com.github.philipjkim.demo.hexagonal.callback"

    @Test
    @DisplayName("domain layer should not depend on any of [application, adapter, external] layers.")
    fun domainLayerDoesNotDependOnOuterLayers() {
      assertDependencyRulesKeptFor(
        basePackage,
        "domain",
        listOf("application", "adapter", "external"),
      )
    }

    @Test
    @DisplayName("application layer should not depend on any of [adapter, external] layers.")
    fun applicationLayerDoesNotDependOnOuterLayers() {
      assertDependencyRulesKeptFor(
        basePackage,
        "application",
        listOf("adapter", "external"),
      )
    }

    @Test
    @DisplayName("adapter layer should not depend on external layer.")
    fun adapterLayerDoesNotDependOnOuterLayers() {
      assertDependencyRulesKeptFor(
        basePackage,
        "adapter",
        listOf("external"),
      )
    }
  }

  @Nested
  @DisplayName("for auth domain")
  inner class ForAuthDomain {
    private val basePackage = "com.github.philipjkim.demo.hexagonal.auth"

    @Test
    @DisplayName("domain layer should not depend on any of [application, adapter, external] layers.")
    fun domainLayerDoesNotDependOnOuterLayers() {
      assertDependencyRulesKeptFor(
        basePackage,
        "domain",
        listOf("application", "adapter", "external"),
      )
    }

    @Test
    @DisplayName("application layer should not depend on any of [adapter, external] layers.")
    fun applicationLayerDoesNotDependOnOuterLayers() {
      assertDependencyRulesKeptFor(
        basePackage,
        "application",
        listOf("adapter", "external"),
      )
    }

    @Test
    @DisplayName("adapter layer should not depend on external layer.")
    fun adapterLayerDoesNotDependOnOuterLayers() {
      assertDependencyRulesKeptFor(
        basePackage,
        "adapter",
        listOf("external"),
      )
    }
  }

  /**
   * Assert that all classes in `basePackage.innerPackage` 
   * do not depend on any classes in `basePackage.outerPackages`.
   *
   * @param basePackage base package of given domain (ex: `com.github.philipjkim.demo.hexagonal.callback`)
   * @param innerPackage the inner package name which is the object of the test (ex: `domain`)
   * @param outerPackages outer packages from the inner package (ex: `[application, adapter, external]`)
   */
  private fun assertDependencyRulesKeptFor(
    basePackage: String,
    innerPackage: String,
    outerPackages: List<String>,
  ) {
    noClasses()
      .that()
      .resideInAPackage("${basePackage}.${innerPackage}..")
      .should()
      .dependOnClassesThat()
      .resideInAnyPackage(
        *(outerPackages.map { "${basePackage}.${it}.." }.toTypedArray())
      )
      .check(ClassFileImporter().importPackages("${basePackage}.."))
  }

  companion object {
    @JvmStatic
    @BeforeAll
    fun setUp() {
      val rootLogger = LoggerFactory.getLogger(Logger.ROOT_LOGGER_NAME) as Logger
      rootLogger.level = Level.INFO
    }
  }
}