diff --git a/hideout-core/build.gradle.kts b/hideout-core/build.gradle.kts
index 88b2bca3..d88f2ac3 100644
--- a/hideout-core/build.gradle.kts
+++ b/hideout-core/build.gradle.kts
@@ -132,6 +132,7 @@ dependencies {
     testImplementation(libs.ktor.client.mock)
     testImplementation(libs.h2db)
     testImplementation(libs.mockito.kotlin)
+    testImplementation("org.assertj:assertj-db:2.0.2")
 }
 
 detekt {
diff --git a/hideout-core/src/test/kotlin/dev/usbharu/hideout/core/infrastructure/exposedrepository/InstanceRepositoryImplTest.kt b/hideout-core/src/test/kotlin/dev/usbharu/hideout/core/infrastructure/exposedrepository/InstanceRepositoryImplTest.kt
new file mode 100644
index 00000000..4755a2cb
--- /dev/null
+++ b/hideout-core/src/test/kotlin/dev/usbharu/hideout/core/infrastructure/exposedrepository/InstanceRepositoryImplTest.kt
@@ -0,0 +1,56 @@
+package dev.usbharu.hideout.core.infrastructure.exposedrepository
+
+import dev.usbharu.hideout.core.domain.model.instance.*
+import dev.usbharu.hideout.core.domain.model.instance.Instance
+import kotlinx.coroutines.test.runTest
+import org.assertj.db.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.TestInstance
+import utils.AbstractRepositoryTest
+import utils.isEqualTo
+import utils.value
+import java.net.URI
+import java.sql.Timestamp
+import java.time.Instant
+import dev.usbharu.hideout.core.infrastructure.exposedrepository.Instance as InstanceTable
+
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+class InstanceRepositoryImplTest : AbstractRepositoryTest(InstanceTable) {
+
+
+    @Test
+    fun save() = runTest {
+        InstanceRepositoryImpl().save(
+            Instance(
+                id = InstanceId(1),
+                name = InstanceName("test"),
+                description = InstanceDescription("id"),
+                url = URI.create("https://www.example.com"),
+                iconUrl = URI.create("https://www.example.com"),
+                sharedInbox = null,
+                software = InstanceSoftware(""),
+                version = InstanceVersion(""),
+                isBlocked = false,
+                isMuted = false,
+                moderationNote = InstanceModerationNote(""),
+                createdAt = Instant.parse("2020-01-01T00:00:00Z"),
+            )
+        )
+
+        val table = assertTable
+        assertThat(table)
+            .row(1)
+            .isEqualTo(InstanceTable.id, 1)
+            .isEqualTo(InstanceTable.name, "test")
+            .isEqualTo(InstanceTable.url, "https://www.example.com")
+            .isEqualTo(InstanceTable.iconUrl, "https://www.example.com")
+            .isEqualTo(InstanceTable.sharedInbox, null)
+            .isEqualTo(InstanceTable.software, "")
+            .isEqualTo(InstanceTable.version, "")
+            .isEqualTo(InstanceTable.isBlocked, false)
+            .isEqualTo(InstanceTable.isMuted, false)
+            .isEqualTo(InstanceTable.moderationNote, "")
+            .value(InstanceTable.createdAt).isEqualTo(Timestamp.from(Instant.parse("2020-01-01T00:00:00Z")))
+    }
+}
+
diff --git a/hideout-core/src/test/kotlin/utils/AbstractRepositoryTest.kt b/hideout-core/src/test/kotlin/utils/AbstractRepositoryTest.kt
new file mode 100644
index 00000000..e2ea2838
--- /dev/null
+++ b/hideout-core/src/test/kotlin/utils/AbstractRepositoryTest.kt
@@ -0,0 +1,85 @@
+package utils
+
+import com.zaxxer.hikari.HikariConfig
+import com.zaxxer.hikari.HikariDataSource
+import org.assertj.db.api.TableRowAssert
+import org.assertj.db.api.TableRowValueAssert
+import org.assertj.db.type.Table
+import org.flywaydb.core.Flyway
+import org.jetbrains.exposed.sql.Column
+import org.jetbrains.exposed.sql.Database
+import org.jetbrains.exposed.sql.DatabaseConfig
+import org.jetbrains.exposed.sql.Transaction
+import org.jetbrains.exposed.sql.transactions.TransactionManager
+import org.junit.jupiter.api.AfterAll
+import org.junit.jupiter.api.AfterEach
+import org.junit.jupiter.api.BeforeAll
+import org.junit.jupiter.api.BeforeEach
+import java.sql.Connection
+import javax.sql.DataSource
+
+abstract class AbstractRepositoryTest(private val exposedTable: org.jetbrains.exposed.sql.Table) {
+
+    protected val assertTable: Table
+        get() {
+            return Table(dataSource, exposedTable.tableName)
+        }
+
+    protected fun getTable(name: String): Table {
+        return Table(dataSource, name)
+    }
+
+    private lateinit var transaction: Transaction
+
+    @BeforeEach
+    fun setUp() {
+        transaction = TransactionManager.currentOrNew(Connection.TRANSACTION_READ_UNCOMMITTED)
+    }
+
+    @AfterEach
+    fun tearDown() {
+        transaction.rollback()
+    }
+
+    companion object {
+
+        lateinit var dataSource: DataSource
+        lateinit var flyway: Flyway
+
+        @JvmStatic
+        @BeforeAll
+        fun setup() {
+            val hikariConfig = HikariConfig()
+            hikariConfig.jdbcUrl =
+                "jdbc:h2:./test;MODE=POSTGRESQL;DB_CLOSE_DELAY=-1;CASE_INSENSITIVE_IDENTIFIERS=true;TRACE_LEVEL_FILE=4;"
+            hikariConfig.driverClassName = "org.h2.Driver"
+            hikariConfig.transactionIsolation = "TRANSACTION_READ_UNCOMMITTED"
+            dataSource = HikariDataSource(hikariConfig)
+
+
+            flyway = Flyway.configure().cleanDisabled(false).dataSource(dataSource).load()
+            val db = Database.connect(dataSource, databaseConfig = DatabaseConfig {
+                this.defaultMaxAttempts = 1
+            })
+            flyway.clean()
+            flyway.migrate()
+        }
+
+        @JvmStatic
+        @AfterAll
+        fun clean() {
+//            flyway.clean()
+        }
+    }
+}
+
+fun <T> TableRowAssert.value(column: Column<T>): TableRowValueAssert = value(column.name)
+fun <T> TableRowValueAssert.value(column: Column<T>): TableRowValueAssert = value(column.name)
+
+fun <T> TableRowAssert.isEqualTo(column: Column<T>, value: T): TableRowValueAssert {
+    return value(column).isEqualTo(value)
+}
+
+fun <T> TableRowValueAssert.isEqualTo(column: Column<T>, value: T): TableRowValueAssert {
+    return value(column).isEqualTo(value)
+}
\ No newline at end of file