add AccountUtil.kt with detectChanges

src/main/kotlin/ltd/hlaeja/util/AccountUtil.kt

@@ -0,0 +1,25 @@
+package ltd.hlaeja.util
+
+import ltd.hlaeja.entity.AccountEntity
+import org.springframework.http.HttpStatus.ACCEPTED
+import org.springframework.web.server.ResponseStatusException
+
+fun AccountEntity.detectChanges(original: AccountEntity): List<String> {
+    val changes: MutableList<String> = mutableListOf()
+    if (original.password != password) {
+        changes.add("password")
+    }
+    if (original.username != username) {
+        changes.add("username")
+    }
+    if (original.enabled != enabled) {
+        changes.add("enabled")
+    }
+    if (original.roles != roles) {
+        changes.add("roles")
+    }
+    if (changes.isEmpty()) {
+        throw ResponseStatusException(ACCEPTED)
+    }
+    return changes
+}

src/test/kotlin/ltd/hlaeja/util/AccountUtilKtTest.kt

@@ -0,0 +1,109 @@
+package ltd.hlaeja.util
+
+import java.time.LocalDateTime
+import java.time.ZoneId
+import java.time.ZonedDateTime
+import java.util.UUID
+import ltd.hlaeja.entity.AccountEntity
+import org.assertj.core.api.SoftAssertions
+import org.assertj.core.api.junit.jupiter.InjectSoftAssertions
+import org.assertj.core.api.junit.jupiter.SoftAssertionsExtension
+import org.junit.jupiter.api.Assertions.assertThrows
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.extension.ExtendWith
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.CsvSource
+import org.springframework.web.server.ResponseStatusException
+
+@ExtendWith(SoftAssertionsExtension::class)
+class AccountUtilKtTest {
+    companion object {
+        val account = UUID.fromString("00000000-0000-0000-0000-000000000000")
+        val timestamp: ZonedDateTime = ZonedDateTime.of(LocalDateTime.of(2000, 1, 1, 0, 0, 0, 1), ZoneId.of("UTC"))
+        val originalUser = AccountEntity(
+            id = account,
+            createdAt = timestamp,
+            updatedAt = timestamp,
+            enabled = true,
+            username = "username",
+            password = "password",
+            roles = "ROLE_TEST",
+        )
+    }
+
+    @InjectSoftAssertions
+    lateinit var softly: SoftAssertions
+
+    @Test
+    fun `no change detected`() {
+        // given
+        val account = AccountEntity(
+            id = account,
+            createdAt = timestamp,
+            updatedAt = timestamp,
+            enabled = true,
+            username = "username",
+            password = "password",
+            roles = "ROLE_TEST",
+        )
+
+        // then exception
+        assertThrows(ResponseStatusException::class.java) {
+            account.detectChanges(originalUser)
+        }
+    }
+
+    @ParameterizedTest
+    @CsvSource(
+        "false, username, password, ROLE_TEST, enabled",
+        "true, change, password, ROLE_TEST, username",
+        "true, username, change, ROLE_TEST, password",
+        "true, username, password, ROLE_CHANGE, roles",
+    )
+    fun `change one thing`(
+        enabled: Boolean,
+        username: String,
+        password: String,
+        roles: String,
+        expected: String,
+    ) {
+        // given
+        val account = AccountEntity(
+            id = account,
+            createdAt = timestamp,
+            updatedAt = timestamp,
+            enabled = enabled,
+            username = username,
+            password = password,
+            roles = roles,
+        )
+
+        // when
+        val result = account.detectChanges(originalUser)
+
+        // then
+        softly.assertThat(result).hasSize(1)
+        softly.assertThat(result[0]).isEqualTo(expected)
+    }
+
+    @Test
+    fun `change everything`() {
+        // given
+        val account = AccountEntity(
+            id = account,
+            createdAt = timestamp,
+            updatedAt = timestamp,
+            enabled = false,
+            username = "change",
+            password = "change",
+            roles = "ROLE_CHANGE",
+        )
+
+        // when
+        val result = account.detectChanges(originalUser)
+
+        // then
+        softly.assertThat(result).hasSize(4)
+        softly.assertThat(result).contains("password", "username", "enabled", "roles")
+    }
+}