diff --git a/src/test/kotlin/dev/usbharu/hideout/service/ap/APRequestServiceImplTest.kt b/src/test/kotlin/dev/usbharu/hideout/service/ap/APRequestServiceImplTest.kt
new file mode 100644
index 00000000..3d77a924
--- /dev/null
+++ b/src/test/kotlin/dev/usbharu/hideout/service/ap/APRequestServiceImplTest.kt
@@ -0,0 +1,348 @@
+package dev.usbharu.hideout.service.ap
+
+import com.fasterxml.jackson.module.kotlin.readValue
+import dev.usbharu.hideout.domain.model.ap.Follow
+import dev.usbharu.hideout.util.Base64Util
+import dev.usbharu.httpsignature.common.HttpHeaders
+import dev.usbharu.httpsignature.common.HttpMethod
+import dev.usbharu.httpsignature.common.HttpRequest
+import dev.usbharu.httpsignature.sign.HttpSignatureSigner
+import dev.usbharu.httpsignature.sign.Signature
+import io.ktor.client.*
+import io.ktor.client.engine.mock.*
+import io.ktor.util.*
+import kotlinx.coroutines.test.runTest
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.Test
+import org.mockito.kotlin.any
+import org.mockito.kotlin.doReturn
+import org.mockito.kotlin.eq
+import org.mockito.kotlin.mock
+import utils.JsonObjectMapper.objectMapper
+import utils.UserBuilder
+import java.net.URL
+import java.security.MessageDigest
+import java.time.format.DateTimeFormatter
+import java.util.*
+
+
+class APRequestServiceImplTest {
+    @Test
+    fun `apGet signerがnullのとき署名なしリクエストをする`() = runTest {
+        val dateTimeFormatter = DateTimeFormatter.ofPattern("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.US)
+        val apRequestServiceImpl = APRequestServiceImpl(
+            HttpClient(MockEngine {
+                assertTrue(it.headers.contains("Date"))
+                assertTrue(it.headers.contains("Accept"))
+                assertFalse(it.headers.contains("Signature"))
+                assertDoesNotThrow {
+                    dateTimeFormatter.parse(it.headers["Date"])
+                }
+                respond("{}")
+            }),
+            objectMapper,
+            mock(),
+            dateTimeFormatter
+        )
+
+        val responseClass = Follow(
+            name = "Follow",
+            `object` = "https://example.com",
+            actor = "https://example.com"
+        )
+        apRequestServiceImpl.apGet("https://example.com", responseClass = responseClass::class.java)
+    }
+
+    @Test
+    fun `apGet signerがnullではないがprivateKeyがnullのとき署名なしリクエストをする`() = runTest {
+        val dateTimeFormatter = DateTimeFormatter.ofPattern("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.US)
+        val apRequestServiceImpl = APRequestServiceImpl(
+            HttpClient(MockEngine {
+                assertTrue(it.headers.contains("Date"))
+                assertTrue(it.headers.contains("Accept"))
+                assertFalse(it.headers.contains("Signature"))
+                assertDoesNotThrow {
+                    dateTimeFormatter.parse(it.headers["Date"])
+                }
+                respond("{}")
+            }),
+            objectMapper,
+            mock(),
+            dateTimeFormatter
+        )
+
+        val responseClass = Follow(
+            name = "Follow",
+            `object` = "https://example.com",
+            actor = "https://example.com"
+        )
+        apRequestServiceImpl.apGet(
+            "https://example.com",
+            UserBuilder.remoteUserOf(),
+            responseClass = responseClass::class.java
+        )
+    }
+
+    @Test
+    fun `apGet signerとprivatekeyがnullではないとき署名付きリクエストをする`() = runTest {
+        val dateTimeFormatter = DateTimeFormatter.ofPattern("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.US)
+        val httpSignatureSigner = mock<HttpSignatureSigner> {
+            onBlocking {
+                sign(
+                    any(),
+                    any(),
+                    eq(listOf("(request-target)", "date", "host", "accept"))
+                )
+            } doReturn Signature(
+                HttpRequest(URL("https://example.com"), HttpHeaders(mapOf()), HttpMethod.GET), "", ""
+            )
+        }
+        val apRequestServiceImpl = APRequestServiceImpl(
+            HttpClient(MockEngine {
+                assertTrue(it.headers.contains("Date"))
+                assertTrue(it.headers.contains("Accept"))
+                assertTrue(it.headers.contains("Signature"))
+                assertDoesNotThrow {
+                    dateTimeFormatter.parse(it.headers["Date"])
+                }
+                respond("{}")
+            }),
+            objectMapper,
+            httpSignatureSigner,
+            dateTimeFormatter
+        )
+
+        val responseClass = Follow(
+            name = "Follow",
+            `object` = "https://example.com",
+            actor = "https://example.com"
+        )
+        apRequestServiceImpl.apGet(
+            "https://example.com",
+            UserBuilder.localUserOf(
+                privateKey = "-----BEGIN PRIVATE KEY-----\n" +
+                        "MIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQDJhNETcFVoZW36\n" +
+                        "pDiaaUDa1FsWGqULUa6jDWYbMXFirbbceJEfvaasac+E8VUQ3krrEhYBArntB1do\n" +
+                        "1Zq/MpI97WaQefwrBmjJwjYglB8AHF1RRqFlJ0aABMBvuHiIzuTPv4dLS4+pJQWl\n" +
+                        "iE9TKsxXgUrEdWLmpSukZpyiWnrgFtJ8322LXRuL9+O4ivns1JfozbrHTprI4ohe\n" +
+                        "6taZJX1mhGBXQT+U/UrEILk+z70P2rrwxwerdO7s6nkkC3ieJWdi924/AopDlg12\n" +
+                        "8udubLPbpWVVrHbSKviUr3VKBKGe4xmvO7hqpGwKmctaXRVPjh/ue2mCIzv3qyxQ\n" +
+                        "3n2Xyhb3AgMBAAECggEAGddiSC/bg+ud0spER+i/XFBm7cq052KuFlKdiVcpxxGn\n" +
+                        "pVYApiVXvjxDVDTuR5950/MZxz9mQDL0zoi1s1b00eQjhttdrta/kT/KWRslboo0\n" +
+                        "nTuFbsc+jyQM2Ua6jjCZvto8qzchUPtiYfu80Floor/9qnuzFwiPNCHEbD1WDG4m\n" +
+                        "fLuH+INnGY6eRF+pgly1dykGs18DaR3vC9CWOqR9PWH+p/myksVymR5adKauMc+l\n" +
+                        "gjLaeB1YjnzXnHYLqwtCgh053kedPG/xZZwq48YNP5npSBIHsd9g8JIPVNOOc6+s\n" +
+                        "bbFqD9aQQxG/WaA5hxHRupLkKGjE6lw4SnVYzKMZIQKBgQDryFa3qzJIBrCQQa0r\n" +
+                        "6YlmZeeCQ8mQL8d0gY0Ixo9Gm2/9J71m/oBkhOqnS6Z5e5UHS5iVaqM7sIOZ2Ony\n" +
+                        "kPADAtxUsk71Il+z+JgyN3OQ+DROLREi2TIWS523hbtN7e/fRFs7KoN6cH7IeF13\n" +
+                        "3pphg9+WWRGX7y1zMd1puY/gSwKBgQDazFrAt/oZbnDhkX350OdIybz62OHNyuZv\n" +
+                        "UX9fFl9i93SF+UhOpJ8YvDJtfLEJUkwO+V3TB+we1OlOYMTqir5M8GFn6YDotwxB\n" +
+                        "r6eT886UpJgtJwswwwW2yaXo7zXaeg3ovRE8RJ4y++Mhuqeq3ajIo7xlhQjzBDEf\n" +
+                        "ZAqasSWwhQKBgQC0VbUlo1XAywUOQH0/oc4KOJS6CDjJBBIsZM3G0X9SBJ7B5Dwz\n" +
+                        "4yG2QAbtT6oTLldMjiA036vbgmUVLVe5w+sekniMexhy2wiRsOhPOCQ20+/Ffyil\n" +
+                        "G7P4Y3tMm4cn0n1tqW2RsjF/Wz1M/OqYPPSc8uz2pEcVisSbX582Nsv5QwKBgEuy\n" +
+                        "vAtFG6BE14UTIzSVFA/YzCs1choTAtqspZauVN4WoxffASdESU7zfbbnlxCUin/7\n" +
+                        "wnxKl2SrYPSfAkHrMp/H4stivBjHi9QGA8JqbaR7tbKZeYOrVYTCC0alzEoERF+r\n" +
+                        "WhUx4FHfV9vJikzRV53jGEE/X7NEVgJ4SDrw4wtJAoGAAMJ2kOIL3HSQPd8csXeU\n" +
+                        "nkxLNzBsFpF76LVmLdzJttlr8HWBjLP/EJFQZFzuf5Hd38cLUOWWD3FRZVw0dUcN\n" +
+                        "RSqfIYT4yDc/9GSRb6rOkdmBUWpTsrZjXBo0MC3p1QE6sNO8JfvmxHTSAe8apBh/\n" +
+                        "gaYuQGh0lNa23HwwFoJxuoc=\n" +
+                        "-----END PRIVATE KEY-----"
+            ),
+            responseClass = responseClass::class.java
+        )
+    }
+
+    @Test
+    fun `apPost bodyがnullでないときcontextにactivitystreamのURLを追加する`() = runTest {
+        val dateTimeFormatter = DateTimeFormatter.ofPattern("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.US)
+        val apRequestServiceImpl = APRequestServiceImpl(HttpClient(MockEngine {
+            val readValue = objectMapper.readValue<Follow>(it.body.toByteArray())
+
+            assertThat(readValue.context).contains("https://www.w3.org/ns/activitystreams")
+
+            respondOk("{}")
+        }), objectMapper, mock(), dateTimeFormatter)
+
+        val body = Follow(
+            name = "Follow",
+            `object` = "https://example.com",
+            actor = "https://example.com"
+        )
+        apRequestServiceImpl.apPost("https://example.com", body, null)
+    }
+
+    @Test
+    fun `apPost bodyがnullのときリクエストボディは空`() = runTest {
+        val dateTimeFormatter = DateTimeFormatter.ofPattern("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.US)
+        val apRequestServiceImpl = APRequestServiceImpl(HttpClient(MockEngine {
+
+            assertEquals(0, it.body.toByteArray().size)
+
+            respondOk("{}")
+        }), objectMapper, mock(), dateTimeFormatter)
+
+        apRequestServiceImpl.apPost("https://example.com", null, null)
+    }
+
+    @Test
+    fun `apPost signerがnullのとき署名なしリクエストをする`() = runTest {
+        val dateTimeFormatter = DateTimeFormatter.ofPattern("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.US)
+        val apRequestServiceImpl = APRequestServiceImpl(HttpClient(MockEngine {
+            val src = it.body.toByteArray()
+            val readValue = objectMapper.readValue<Follow>(src)
+
+            assertThat(readValue.context).contains("https://www.w3.org/ns/activitystreams")
+
+            val map = it.headers.toMap()
+            assertThat(map).containsKey("Date")
+                .containsKey("Digest")
+                .containsKey("Accept")
+                .doesNotContainKey("Signature")
+
+            assertDoesNotThrow {
+                dateTimeFormatter.parse(it.headers["Date"])
+            }
+            val messageDigest = MessageDigest.getInstance("SHA-256")
+            val digest = Base64Util.encode(messageDigest.digest(src))
+
+            assertEquals(digest, it.headers["Digest"].orEmpty().split("256=").last())
+
+            respondOk("{}")
+        }), objectMapper, mock(), dateTimeFormatter)
+
+        val body = Follow(
+            name = "Follow",
+            `object` = "https://example.com",
+            actor = "https://example.com"
+        )
+        apRequestServiceImpl.apPost("https://example.com", body, null)
+    }
+
+    @Test
+    fun `apPost signerがnullではないがprivatekeyがnullのとき署名なしリクエストをする`() = runTest {
+        val dateTimeFormatter = DateTimeFormatter.ofPattern("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.US)
+        val apRequestServiceImpl = APRequestServiceImpl(HttpClient(MockEngine {
+            val src = it.body.toByteArray()
+            val readValue = objectMapper.readValue<Follow>(src)
+
+            assertThat(readValue.context).contains("https://www.w3.org/ns/activitystreams")
+
+            val map = it.headers.toMap()
+            assertThat(map).containsKey("Date")
+                .containsKey("Digest")
+                .containsKey("Accept")
+                .doesNotContainKey("Signature")
+
+            val messageDigest = MessageDigest.getInstance("SHA-256")
+            val digest = Base64Util.encode(messageDigest.digest(src))
+
+            assertEquals(digest, it.headers["Digest"].orEmpty().split("256=").last())
+
+            respondOk("{}")
+        }), objectMapper, mock(), dateTimeFormatter)
+
+        val body = Follow(
+            name = "Follow",
+            `object` = "https://example.com",
+            actor = "https://example.com"
+        )
+        apRequestServiceImpl.apPost("https://example.com", body, UserBuilder.remoteUserOf())
+    }
+
+    @Test
+    fun `apPost signerがnullではないとき署名付きリクエストをする`() = runTest {
+        val dateTimeFormatter = DateTimeFormatter.ofPattern("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.US)
+        val httpSignatureSigner = mock<HttpSignatureSigner> {
+            onBlocking {
+                sign(
+                    any(),
+                    any(),
+                    eq(listOf("(request-target)", "date", "host", "digest"))
+                )
+            } doReturn Signature(
+                HttpRequest(URL("https://example.com"), HttpHeaders(mapOf()), HttpMethod.POST), "", ""
+            )
+        }
+        val apRequestServiceImpl = APRequestServiceImpl(HttpClient(MockEngine {
+            val src = it.body.toByteArray()
+            val readValue = objectMapper.readValue<Follow>(src)
+
+            assertThat(readValue.context).contains("https://www.w3.org/ns/activitystreams")
+
+            val map = it.headers.toMap()
+            assertThat(map).containsKey("Date")
+                .containsKey("Digest")
+                .containsKey("Accept")
+                .containsKey("Signature")
+
+            val messageDigest = MessageDigest.getInstance("SHA-256")
+            val digest = Base64Util.encode(messageDigest.digest(src))
+
+            assertEquals(digest, it.headers["Digest"].orEmpty().split("256=").last())
+
+            respondOk("{}")
+        }), objectMapper, httpSignatureSigner, dateTimeFormatter)
+
+        val body = Follow(
+            name = "Follow",
+            `object` = "https://example.com",
+            actor = "https://example.com"
+        )
+        apRequestServiceImpl.apPost(
+            "https://example.com", body, UserBuilder.localUserOf(
+                privateKey = "-----BEGIN PRIVATE KEY-----\n" +
+                        "MIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQC1+pj+/t5WwU6P\n" +
+                        "OiaAKfOHCUVMdOR5e2Jp0BUYfAFpim27pLsHRXVjdzs+D4gvDnQWC0FMltPyBldk\n" +
+                        "gjisNMtTKgTTsYhlLlSi+yRDZvIQyH4b7xSX0hCeflTrTkt18ZldBRPfMHE0KSho\n" +
+                        "mm3Lc7ubF32YzGoo3A3qEVDAR9dVQOnt/GXLiN4RHoStX+y5UiP6B4s49nyEwuLm\n" +
+                        "+HE4ph3Loqn0dTEL4cEuI8ZX51J3mTKT3rmMo0wCXXOm8gD2Fu7hYEdr9ulWF8GO\n" +
+                        "yVe7Miu9prbBlY/r4skdXc5o6uE8tsPT88Ly9lSr3xqbmn1/EhyqBRdcyoj28C65\n" +
+                        "cThO38jvAgMBAAECggEAFbOaXkJ3smHgI/17zOnz1EU7QehovMIFlPfPJDnZk0QC\n" +
+                        "XQ/CjBXw71kvM/H3PCFdn6lc8qzD/sdZ0a8j4glzu+m1ZKd1zBcv2bXYd79Fm9HF\n" +
+                        "FEC5NHfFKpmHN/6AykJzFyA9Y+7reRx1aLAN6ubU1ySAgmHSQSgo8qJ4/k0y9UQS\n" +
+                        "EbjxQL5ziXuxRBMn7InLUGLl5UfCC0V1R8MZQAe+fApKDXMQ0LHSJUg1A365PyhV\n" +
+                        "seotqvhurHH3UVHf5n0/sFeqp2hI4ymR3cs4kd8IuNIXE7afh+89IyuVKMvJh+iQ\n" +
+                        "ZGO1RL0v0mNtUpI81agSrrQ4LRBjSkP+5s5PdXTrSQKBgQD2lwMXLylhQzhRyhLx\n" +
+                        "sSPRf9mKDUcretwA5Fh9GuAurKOz7SvIdzrUPFYUTUKSTwk8mVRRamkFtJ8IOB7Z\n" +
+                        "MLenlFqxs4XrNGBcZxut5cPv68xn2F00Y4HwX9xmEi+vniNVrDpdVLxEoVfm1pBk\n" +
+                        "02ZHCcfYVN0t8dnvXvlL+eJSqQKBgQC87GMoMvFnWgT23wdXtQH+F+gQAMUrkMWz\n" +
+                        "Ld2uRwuSVQArgp+YgnwWMlYlFp/QIW90t7UVmf6bHIplO5bL2OwayIO1r/WxD1eN\n" +
+                        "RLrFIeDbtCZWQTHUypnWtl+9lrh/RrCjZo/sZFl07OSIKgGM37j9taG6Nv6fV7gv\n" +
+                        "T0q6eDCV1wKBgGh3CUQlIq6lv5JGvUfO95GlTA+EGIZ/Af0Ov74gSKD9Wky7STUf\n" +
+                        "7bhD52OqZ218NjmJ64KiReO45TaiL89rKCLCYrmtiCpgggIjXEKLeDqH9ox3yOSM\n" +
+                        "01t2APTs926629VLpV4sq6WXhJmyhHFybX3i0tr++MSiFOWnoo1hS1QhAoGAfVY6\n" +
+                        "ppW9kDqppnrqrSZ6Lu//VnacWL3QW4JnWtLpe2iHF1auuQiAeF1mx25OEk/MWNvz\n" +
+                        "+GPVBWUW7/hrn8vHQDGdJ/GYB6LNC/z4CAbk3f2TnY/dFnZfP5J4zBftSQtF7vIB\n" +
+                        "M+yTaL4tE6UCqEpYuYFBzX/kxyP0Hvb09eb9HLsCgYEArFSgWpaLbADcWd+ygWls\n" +
+                        "LNfch1Yl2bnqXKz1Dnw3J4l2gbVNcABXQLrB6upjtkytxj4ae66Sio7nf+dB5yJ6\n" +
+                        "NVY7i4C0JrniY2OvLnuz2bKpaTgMPJxyZqGQ6Vu2b3x9WhcpiI83SCuCUgBKxjh/\n" +
+                        "qEGv2ZqFfnNVrz5RXLHBoG4=\n" +
+                        "-----END PRIVATE KEY-----"
+            )
+        )
+    }
+
+    @Test
+    fun `apPost responseClassを指定した場合はjsonでシリアライズされる`() = runTest {
+        val dateTimeFormatter = DateTimeFormatter.ofPattern("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.US)
+        val apRequestServiceImpl = APRequestServiceImpl(HttpClient(MockEngine {
+            val src = it.body.toByteArray()
+            val readValue = objectMapper.readValue<Follow>(src)
+
+            assertThat(readValue.context).contains("https://www.w3.org/ns/activitystreams")
+
+            respondOk(src.decodeToString())
+        }), objectMapper, mock(), dateTimeFormatter)
+
+        val body = Follow(
+            name = "Follow",
+            `object` = "https://example.com",
+            actor = "https://example.com"
+        )
+        val actual = apRequestServiceImpl.apPost("https://example.com", body, null, body::class.java)
+
+        assertThat(body).isEqualTo(actual)
+    }
+}
diff --git a/src/test/kotlin/utils/UserBuilder.kt b/src/test/kotlin/utils/UserBuilder.kt
index 9d8116cd..d3294786 100644
--- a/src/test/kotlin/utils/UserBuilder.kt
+++ b/src/test/kotlin/utils/UserBuilder.kt
@@ -13,7 +13,7 @@ object UserBuilder {
 
     private val idGenerator = TwitterSnowflakeIdGenerateService
 
-    suspend fun localUserOf(
+    fun localUserOf(
         id: Long = generateId(),
         name: String = "test-user-$id",
         domain: String = "example.com",
@@ -49,6 +49,40 @@ object UserBuilder {
         )
     }
 
+    fun remoteUserOf(
+        id: Long = generateId(),
+        name: String = "test-user-$id",
+        domain: String = "remote.example.com",
+        screenName: String = name,
+        description: String = "This user is test user.",
+        inbox: String = "https://$domain/$id/inbox",
+        outbox: String = "https://$domain/$id/outbox",
+        url: String = "https://$domain/$id/",
+        publicKey: String = "-----BEGIN PUBLIC KEY-----...-----END PUBLIC KEY-----",
+        createdAt: Instant = Instant.now(),
+        keyId: String = "https://$domain/$id#pubkey",
+        followers: String = "https://$domain/$id/followers",
+        following: String = "https://$domain/$id/following"
+    ): User {
+        return userBuilder.of(
+            id = id,
+            name = name,
+            domain = domain,
+            screenName = screenName,
+            description = description,
+            password = null,
+            inbox = inbox,
+            outbox = outbox,
+            url = url,
+            publicKey = publicKey,
+            privateKey = null,
+            createdAt = createdAt,
+            keyId = keyId,
+            followers = following,
+            following = followers
+        )
+    }
+
     private fun generateId(): Long = runBlocking {
         idGenerator.generateId()
     }