feat: add board detail and card/list mutation API methods

app/src/androidTest/java/space/hackenslacker/kanbn4droid/app/BoardsFlowTest.kt

@@ -24,6 +24,7 @@ import space.hackenslacker.kanbn4droid.app.auth.ApiKeyStore
 import space.hackenslacker.kanbn4droid.app.auth.AuthResult
 import space.hackenslacker.kanbn4droid.app.auth.KanbnApiClient
 import space.hackenslacker.kanbn4droid.app.auth.SessionStore
+import space.hackenslacker.kanbn4droid.app.boarddetail.BoardDetail
 import space.hackenslacker.kanbn4droid.app.boards.BoardSummary
 import space.hackenslacker.kanbn4droid.app.boards.BoardTemplate
 import space.hackenslacker.kanbn4droid.app.boards.BoardsApiResult
@@ -199,5 +200,31 @@ class BoardsFlowTest {
             boards.removeAll { it.id == boardId }
             return BoardsApiResult.Success(Unit)
         }
+
+        override suspend fun getBoardDetail(baseUrl: String, apiKey: String, boardId: String): BoardsApiResult<BoardDetail> {
+            return BoardsApiResult.Failure("Not used in this test")
+        }
+
+        override suspend fun renameList(
+            baseUrl: String,
+            apiKey: String,
+            listId: String,
+            newTitle: String,
+        ): BoardsApiResult<Unit> {
+            return BoardsApiResult.Failure("Not used in this test")
+        }
+
+        override suspend fun moveCard(
+            baseUrl: String,
+            apiKey: String,
+            cardId: String,
+            targetListId: String,
+        ): BoardsApiResult<Unit> {
+            return BoardsApiResult.Failure("Not used in this test")
+        }
+
+        override suspend fun deleteCard(baseUrl: String, apiKey: String, cardId: String): BoardsApiResult<Unit> {
+            return BoardsApiResult.Failure("Not used in this test")
+        }
     }
 }

app/src/androidTest/java/space/hackenslacker/kanbn4droid/app/LoginFlowTest.kt

@@ -22,6 +22,8 @@ import space.hackenslacker.kanbn4droid.app.auth.ApiKeyStore
 import space.hackenslacker.kanbn4droid.app.auth.AuthResult
 import space.hackenslacker.kanbn4droid.app.auth.KanbnApiClient
 import space.hackenslacker.kanbn4droid.app.auth.SessionStore
+import space.hackenslacker.kanbn4droid.app.boarddetail.BoardDetail
+import space.hackenslacker.kanbn4droid.app.boards.BoardsApiResult
 
 @RunWith(AndroidJUnit4::class)
 class LoginFlowTest {
@@ -200,5 +202,31 @@ class LoginFlowTest {
         private val result: AuthResult,
     ) : KanbnApiClient {
         override suspend fun healthCheck(baseUrl: String, apiKey: String): AuthResult = result
+
+        override suspend fun getBoardDetail(baseUrl: String, apiKey: String, boardId: String): BoardsApiResult<BoardDetail> {
+            return BoardsApiResult.Failure("Not used in this test")
+        }
+
+        override suspend fun renameList(
+            baseUrl: String,
+            apiKey: String,
+            listId: String,
+            newTitle: String,
+        ): BoardsApiResult<Unit> {
+            return BoardsApiResult.Failure("Not used in this test")
+        }
+
+        override suspend fun moveCard(
+            baseUrl: String,
+            apiKey: String,
+            cardId: String,
+            targetListId: String,
+        ): BoardsApiResult<Unit> {
+            return BoardsApiResult.Failure("Not used in this test")
+        }
+
+        override suspend fun deleteCard(baseUrl: String, apiKey: String, cardId: String): BoardsApiResult<Unit> {
+            return BoardsApiResult.Failure("Not used in this test")
+        }
     }
 }

app/src/main/java/space/hackenslacker/kanbn4droid/app/auth/KanbnApiClient.kt

@@ -3,10 +3,15 @@ package space.hackenslacker.kanbn4droid.app.auth
 import java.io.IOException
 import java.net.HttpURLConnection
 import java.net.URL
+import java.time.Instant
 import org.json.JSONArray
 import org.json.JSONObject
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
+import space.hackenslacker.kanbn4droid.app.boarddetail.BoardCardSummary
+import space.hackenslacker.kanbn4droid.app.boarddetail.BoardDetail
+import space.hackenslacker.kanbn4droid.app.boarddetail.BoardListDetail
+import space.hackenslacker.kanbn4droid.app.boarddetail.BoardTagSummary
 import space.hackenslacker.kanbn4droid.app.boards.BoardSummary
 import space.hackenslacker.kanbn4droid.app.boards.BoardTemplate
 import space.hackenslacker.kanbn4droid.app.boards.BoardsApiResult
@@ -48,6 +53,22 @@ interface KanbnApiClient {
     suspend fun deleteBoard(baseUrl: String, apiKey: String, boardId: String): BoardsApiResult<Unit> {
         return BoardsApiResult.Failure("Board deletion is not implemented.")
     }
+
+    suspend fun getBoardDetail(baseUrl: String, apiKey: String, boardId: String): BoardsApiResult<BoardDetail> {
+        return BoardsApiResult.Failure("Board detail is not implemented.")
+    }
+
+    suspend fun renameList(baseUrl: String, apiKey: String, listId: String, newTitle: String): BoardsApiResult<Unit> {
+        return BoardsApiResult.Failure("List rename is not implemented.")
+    }
+
+    suspend fun moveCard(baseUrl: String, apiKey: String, cardId: String, targetListId: String): BoardsApiResult<Unit> {
+        return BoardsApiResult.Failure("Card move is not implemented.")
+    }
+
+    suspend fun deleteCard(baseUrl: String, apiKey: String, cardId: String): BoardsApiResult<Unit> {
+        return BoardsApiResult.Failure("Card deletion is not implemented.")
+    }
 }
 
 class HttpKanbnApiClient : KanbnApiClient {
@@ -193,6 +214,94 @@ class HttpKanbnApiClient : KanbnApiClient {
         }
     }
 
+    override suspend fun getBoardDetail(
+        baseUrl: String,
+        apiKey: String,
+        boardId: String,
+    ): BoardsApiResult<BoardDetail> {
+        return withContext(Dispatchers.IO) {
+            request(
+                baseUrl = baseUrl,
+                path = "/api/v1/boards/$boardId",
+                method = "GET",
+                apiKey = apiKey,
+            ) { code, body ->
+                if (code in 200..299) {
+                    BoardsApiResult.Success(parseBoardDetail(body, boardId))
+                } else {
+                    BoardsApiResult.Failure(serverMessage(body, code))
+                }
+            }
+        }
+    }
+
+    override suspend fun renameList(
+        baseUrl: String,
+        apiKey: String,
+        listId: String,
+        newTitle: String,
+    ): BoardsApiResult<Unit> {
+        return withContext(Dispatchers.IO) {
+            request(
+                baseUrl = baseUrl,
+                path = "/api/v1/lists/$listId",
+                method = "PATCH",
+                apiKey = apiKey,
+                body = "{\"name\":\"${jsonEscape(newTitle.trim())}\"}",
+            ) { code, body ->
+                if (code in 200..299) {
+                    BoardsApiResult.Success(Unit)
+                } else {
+                    BoardsApiResult.Failure(serverMessage(body, code))
+                }
+            }
+        }
+    }
+
+    override suspend fun moveCard(
+        baseUrl: String,
+        apiKey: String,
+        cardId: String,
+        targetListId: String,
+    ): BoardsApiResult<Unit> {
+        return withContext(Dispatchers.IO) {
+            request(
+                baseUrl = baseUrl,
+                path = "/api/v1/cards/$cardId",
+                method = "PATCH",
+                apiKey = apiKey,
+                body = "{\"listId\":\"${jsonEscape(targetListId)}\"}",
+            ) { code, body ->
+                if (code in 200..299) {
+                    BoardsApiResult.Success(Unit)
+                } else {
+                    BoardsApiResult.Failure(serverMessage(body, code))
+                }
+            }
+        }
+    }
+
+    override suspend fun deleteCard(
+        baseUrl: String,
+        apiKey: String,
+        cardId: String,
+    ): BoardsApiResult<Unit> {
+        return withContext(Dispatchers.IO) {
+            request(
+                baseUrl = baseUrl,
+                path = "/api/v1/cards/$cardId",
+                method = "DELETE",
+                apiKey = apiKey,
+            ) { code, body ->
+                if (code in 200..299) {
+                    BoardsApiResult.Success(Unit)
+                } else {
+                    BoardsApiResult.Failure(serverMessage(body, code))
+                }
+            }
+        }
+    }
+
     private fun <T> request(
         baseUrl: String,
         path: String,
@@ -203,7 +312,7 @@ class HttpKanbnApiClient : KanbnApiClient {
     ): BoardsApiResult<T> {
         val endpoint = "${baseUrl.trimEnd('/')}$path"
         val connection = (URL(endpoint).openConnection() as HttpURLConnection).apply {
-            requestMethod = method
+            configureRequestMethod(this, method)
             connectTimeout = 10_000
             readTimeout = 10_000
             setRequestProperty("x-api-key", apiKey)
@@ -237,6 +346,18 @@ class HttpKanbnApiClient : KanbnApiClient {
         }
     }
 
+    private fun configureRequestMethod(connection: HttpURLConnection, method: String) {
+        try {
+            connection.requestMethod = method
+        } catch (throwable: Throwable) {
+            if (method != "PATCH") {
+                throw throwable
+            }
+            connection.requestMethod = "POST"
+            connection.setRequestProperty("X-HTTP-Method-Override", "PATCH")
+        }
+    }
+
     private fun readResponseBody(connection: HttpURLConnection, code: Int): String {
         val stream = if (code in 200..299) connection.inputStream else connection.errorStream
         return stream?.bufferedReader()?.use { it.readText() }.orEmpty()
@@ -361,18 +482,295 @@ class HttpKanbnApiClient : KanbnApiClient {
         return workspaces
     }
 
+    private fun parseBoardDetail(body: String, fallbackId: String): BoardDetail {
+        val root = parseJsonObject(body)
+            ?: return BoardDetail(id = fallbackId, title = "Board", lists = emptyList())
+        val data = root["data"] as? Map<*, *>
+        val board = (data?.get("board") as? Map<*, *>)
+            ?: (root["board"] as? Map<*, *>)
+            ?: root
+
+        val boardId = extractId(board).ifBlank { fallbackId }
+        val boardTitle = extractTitle(board, "Board")
+        val lists = parseLists(board)
+
+        return BoardDetail(id = boardId, title = boardTitle, lists = lists)
+    }
+
+    private fun parseLists(board: Map<*, *>): List<BoardListDetail> {
+        return extractObjectArray(board, "lists", "items", "data").mapNotNull { rawList ->
+            val id = extractId(rawList)
+            if (id.isBlank()) {
+                return@mapNotNull null
+            }
+            BoardListDetail(
+                id = id,
+                title = extractTitle(rawList, "List"),
+                cards = parseCards(rawList),
+            )
+        }
+    }
+
+    private fun parseCards(list: Map<*, *>): List<BoardCardSummary> {
+        return extractObjectArray(list, "cards", "items", "data").mapNotNull { rawCard ->
+            val id = extractId(rawCard)
+            if (id.isBlank()) {
+                return@mapNotNull null
+            }
+            BoardCardSummary(
+                id = id,
+                title = extractTitle(rawCard, "Card"),
+                tags = parseTags(rawCard),
+                dueAtEpochMillis = parseDueDate(rawCard),
+            )
+        }
+    }
+
+    private fun parseTags(card: Map<*, *>): List<BoardTagSummary> {
+        return extractObjectArray(card, "labels", "tags", "data").mapNotNull { rawTag ->
+            val id = extractId(rawTag)
+            if (id.isBlank()) {
+                return@mapNotNull null
+            }
+            BoardTagSummary(
+                id = id,
+                name = extractTitle(rawTag, "Tag"),
+                colorHex = extractString(rawTag, "colorHex", "color", "hex"),
+            )
+        }
+    }
+
+    private fun parseDueDate(card: Map<*, *>): Long? {
+        val dueValue = firstPresent(card, "dueDate", "dueAt", "due_at", "due") ?: return null
+        return when (dueValue) {
+            is Number -> dueValue.toLong()
+            is String -> {
+                val trimmed = dueValue.trim()
+                if (trimmed.isBlank()) null else trimmed.toLongOrNull() ?: runCatching { Instant.parse(trimmed).toEpochMilli() }.getOrNull()
+            }
+
+            else -> null
+        }
+    }
+
+    private fun extractObjectArray(source: Map<*, *>, vararg keys: String): List<Map<*, *>> {
+        val array = keys.firstNotNullOfOrNull { key -> source[key] as? List<*> } ?: return emptyList()
+        return array.mapNotNull { it as? Map<*, *> }
+    }
+
+    private fun extractId(source: Map<*, *>): String {
+        val directId = source["id"]?.toString().orEmpty()
+        if (directId.isNotBlank()) {
+            return directId
+        }
+        return extractString(source, "publicId", "public_id")
+    }
+
+    private fun extractTitle(source: Map<*, *>, fallback: String): String {
+        return extractString(source, "title", "name").ifBlank { fallback }
+    }
+
+    private fun extractString(source: Map<*, *>, vararg keys: String): String {
+        return keys.firstNotNullOfOrNull { key -> source[key]?.toString()?.takeIf { it.isNotBlank() } }.orEmpty()
+    }
+
+    private fun firstPresent(source: Map<*, *>, vararg keys: String): Any? {
+        return keys.firstNotNullOfOrNull { key -> source[key] }
+    }
+
+    private fun parseJsonObject(body: String): Map<String, Any?>? {
+        val trimmed = body.trim()
+        if (trimmed.isBlank()) {
+            return null
+        }
+        val parsed = runCatching { MiniJsonParser(trimmed).parseValue() }.getOrNull()
+        @Suppress("UNCHECKED_CAST")
+        return parsed as? Map<String, Any?>
+    }
+
+    private fun jsonEscape(value: String): String {
+        val builder = StringBuilder()
+        value.forEach { ch ->
+            when (ch) {
+                '\\' -> builder.append("\\\\")
+                '"' -> builder.append("\\\"")
+                '\b' -> builder.append("\\b")
+                '\u000C' -> builder.append("\\f")
+                '\n' -> builder.append("\\n")
+                '\r' -> builder.append("\\r")
+                '\t' -> builder.append("\\t")
+                else -> builder.append(ch)
+            }
+        }
+        return builder.toString()
+    }
+
+    private class MiniJsonParser(private val input: String) {
+        private var index = 0
+
+        fun parseValue(): Any? {
+            skipWhitespace()
+            if (index >= input.length) {
+                return null
+            }
+            return when (val ch = input[index]) {
+                '{' -> parseObject()
+                '[' -> parseArray()
+                '"' -> parseString()
+                't' -> parseLiteral("true", true)
+                'f' -> parseLiteral("false", false)
+                'n' -> parseLiteral("null", null)
+                '-', in '0'..'9' -> parseNumber()
+                else -> throw IllegalArgumentException("Unexpected token $ch at index $index")
+            }
+        }
+
+        private fun parseObject(): Map<String, Any?> {
+            expect('{')
+            skipWhitespace()
+            val result = linkedMapOf<String, Any?>()
+            if (peek() == '}') {
+                index += 1
+                return result
+            }
+            while (index < input.length) {
+                val key = parseString()
+                skipWhitespace()
+                expect(':')
+                val value = parseValue()
+                result[key] = value
+                skipWhitespace()
+                when (peek()) {
+                    ',' -> index += 1
+                    '}' -> {
+                        index += 1
+                        return result
+                    }
+                    else -> throw IllegalArgumentException("Expected , or } at index $index")
+                }
+                skipWhitespace()
+            }
+            throw IllegalArgumentException("Unclosed object")
+        }
+
+        private fun parseArray(): List<Any?> {
+            expect('[')
+            skipWhitespace()
+            val result = mutableListOf<Any?>()
+            if (peek() == ']') {
+                index += 1
+                return result
+            }
+            while (index < input.length) {
+                result += parseValue()
+                skipWhitespace()
+                when (peek()) {
+                    ',' -> index += 1
+                    ']' -> {
+                        index += 1
+                        return result
+                    }
+                    else -> throw IllegalArgumentException("Expected , or ] at index $index")
+                }
+                skipWhitespace()
+            }
+            throw IllegalArgumentException("Unclosed array")
+        }
+
+        private fun parseString(): String {
+            expect('"')
+            val result = StringBuilder()
+            while (index < input.length) {
+                val ch = input[index++]
+                when (ch) {
+                    '"' -> return result.toString()
+                    '\\' -> {
+                        val escaped = input.getOrNull(index++) ?: throw IllegalArgumentException("Invalid escape")
+                        when (escaped) {
+                            '"' -> result.append('"')
+                            '\\' -> result.append('\\')
+                            '/' -> result.append('/')
+                            'b' -> result.append('\b')
+                            'f' -> result.append('\u000C')
+                            'n' -> result.append('\n')
+                            'r' -> result.append('\r')
+                            't' -> result.append('\t')
+                            'u' -> {
+                                val hex = input.substring(index, index + 4)
+                                index += 4
+                                result.append(hex.toInt(16).toChar())
+                            }
+                            else -> throw IllegalArgumentException("Invalid escape token")
+                        }
+                    }
+                    else -> result.append(ch)
+                }
+            }
+            throw IllegalArgumentException("Unclosed string")
+        }
+
+        private fun parseNumber(): Any {
+            val start = index
+            if (peek() == '-') {
+                index += 1
+            }
+            while (peek()?.isDigit() == true) {
+                index += 1
+            }
+            var isFloating = false
+            if (peek() == '.') {
+                isFloating = true
+                index += 1
+                while (peek()?.isDigit() == true) {
+                    index += 1
+                }
+            }
+            if (peek() == 'e' || peek() == 'E') {
+                isFloating = true
+                index += 1
+                if (peek() == '+' || peek() == '-') {
+                    index += 1
+                }
+                while (peek()?.isDigit() == true) {
+                    index += 1
+                }
+            }
+            val token = input.substring(start, index)
+            return if (isFloating) token.toDouble() else token.toLong()
+        }
+
+        private fun parseLiteral(token: String, value: Any?): Any? {
+            if (!input.startsWith(token, index)) {
+                throw IllegalArgumentException("Expected $token at index $index")
+            }
+            index += token.length
+            return value
+        }
+
+        private fun expect(expected: Char) {
+            skipWhitespace()
+            if (peek() != expected) {
+                throw IllegalArgumentException("Expected $expected at index $index")
+            }
+            index += 1
+        }
+
+        private fun peek(): Char? = input.getOrNull(index)
+
+        private fun skipWhitespace() {
+            while (peek()?.isWhitespace() == true) {
+                index += 1
+            }
+        }
+    }
+
     private fun serverMessage(body: String, code: Int): String {
         if (body.isBlank()) {
             return "Server error: $code"
         }
 
-        return runCatching {
-            val root = JSONObject(body)
-            listOf("message", "error", "cause", "detail")
-                .firstNotNullOfOrNull { key -> root.optString(key).takeIf { it.isNotBlank() } }
-                ?: "Server error: $code"
-        }.getOrElse {
-            "Server error: $code"
-        }
+        val root = parseJsonObject(body)
+        val message = root?.let { extractString(it, "message", "error", "cause", "detail") }.orEmpty()
+        return message.ifBlank { "Server error: $code" }
     }
 }

app/src/test/java/space/hackenslacker/kanbn4droid/app/auth/HttpKanbnApiClientBoardDetailParsingTest.kt

@@ -0,0 +1,357 @@
+package space.hackenslacker.kanbn4droid.app.auth
+
+import java.io.BufferedInputStream
+import java.io.OutputStream
+import java.net.InetSocketAddress
+import java.net.ServerSocket
+import java.net.Socket
+import java.time.Instant
+import java.util.concurrent.CopyOnWriteArrayList
+import java.util.concurrent.Executors
+import java.util.concurrent.TimeUnit
+import java.util.concurrent.atomic.AtomicBoolean
+import kotlinx.coroutines.test.runTest
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNotNull
+import org.junit.Assert.assertNull
+import org.junit.Assert.assertTrue
+import org.junit.Test
+import space.hackenslacker.kanbn4droid.app.boarddetail.BoardDetail
+import space.hackenslacker.kanbn4droid.app.boards.BoardsApiResult
+
+class HttpKanbnApiClientBoardDetailParsingTest {
+
+    @Test
+    fun getBoardDetailParsesWrappedPayloadWithDueDateVariants() = runTest {
+        TestServer().use { server ->
+            server.register(
+                path = "/api/v1/boards/board-1",
+                status = 200,
+                responseBody =
+                    """
+                    {
+                      "data": {
+                        "board": {
+                          "public_id": "board-1",
+                          "name": "Roadmap",
+                          "items": [
+                            {
+                              "id": "list-1",
+                              "name": "Todo",
+                              "cards": [
+                                {
+                                  "publicId": "card-iso",
+                                  "name": "ISO",
+                                  "tags": [{"id": "tag-1", "name": "Urgent", "color": "#FF0000"}],
+                                  "dueAt": "2026-01-05T08:30:00Z"
+                                },
+                                {
+                                  "public_id": "card-epoch-num",
+                                  "title": "EpochNum",
+                                  "labels": [{"public_id": "tag-2", "title": "Backend", "colorHex": "#00FF00"}],
+                                  "due": 1735689600000
+                                }
+                              ]
+                            },
+                            {
+                              "publicId": "list-2",
+                              "title": "Doing",
+                              "data": [
+                                {
+                                  "id": "card-epoch-string",
+                                  "title": "EpochString",
+                                  "data": [{"id": "tag-3", "name": "Ops", "hex": "#0000FF"}],
+                                  "due_at": "1735689600123"
+                                },
+                                {
+                                  "id": "card-invalid",
+                                  "name": "Invalid",
+                                  "labels": [],
+                                  "dueDate": "not-a-date"
+                                }
+                              ]
+                            }
+                          ]
+                        }
+                      }
+                    }
+                    """.trimIndent(),
+            )
+
+            val client = HttpKanbnApiClient()
+
+            val result = client.getBoardDetail(server.baseUrl, "api-key", "board-1")
+
+            assertTrue(result is BoardsApiResult.Success<*>)
+            val detail = (result as BoardsApiResult.Success<*>).value as BoardDetail
+            assertEquals("board-1", detail.id)
+            assertEquals("Roadmap", detail.title)
+            assertEquals(2, detail.lists.size)
+            assertEquals("list-1", detail.lists[0].id)
+            assertEquals("Todo", detail.lists[0].title)
+            assertEquals("card-iso", detail.lists[0].cards[0].id)
+            assertEquals(Instant.parse("2026-01-05T08:30:00Z").toEpochMilli(), detail.lists[0].cards[0].dueAtEpochMillis)
+            assertEquals(1735689600000L, detail.lists[0].cards[1].dueAtEpochMillis)
+            assertEquals("tag-1", detail.lists[0].cards[0].tags[0].id)
+            assertEquals("Urgent", detail.lists[0].cards[0].tags[0].name)
+            assertEquals("#FF0000", detail.lists[0].cards[0].tags[0].colorHex)
+            assertEquals(1735689600123L, detail.lists[1].cards[0].dueAtEpochMillis)
+            assertNull(detail.lists[1].cards[1].dueAtEpochMillis)
+        }
+    }
+
+    @Test
+    fun getBoardDetailParsesDirectRootObject() = runTest {
+        TestServer().use { server ->
+            server.register(
+                path = "/api/v1/boards/b-2",
+                status = 200,
+                responseBody =
+                    """
+                    {
+                      "id": "b-2",
+                      "title": "Board Direct",
+                      "lists": [
+                        {
+                          "id": "l-1",
+                          "title": "List",
+                          "cards": [
+                            {
+                              "id": "c-1",
+                              "title": "Card",
+                              "labels": [{"id": "t-1", "name": "Tag", "color": "#111111"}]
+                            }
+                          ]
+                        }
+                      ]
+                    }
+                    """.trimIndent(),
+            )
+
+            val result = HttpKanbnApiClient().getBoardDetail(server.baseUrl, "key", "b-2")
+
+            assertTrue(result is BoardsApiResult.Success<*>)
+            val detail = (result as BoardsApiResult.Success<*>).value as BoardDetail
+            assertEquals("b-2", detail.id)
+            assertEquals("Board Direct", detail.title)
+            assertEquals(1, detail.lists.size)
+            assertEquals("l-1", detail.lists[0].id)
+            assertEquals("c-1", detail.lists[0].cards[0].id)
+            assertEquals("t-1", detail.lists[0].cards[0].tags[0].id)
+        }
+    }
+
+    @Test
+    fun requestMappingMatchesContractForBoardDetailAndMutations() = runTest {
+        TestServer().use { server ->
+            server.register(
+                path = "/api/v1/boards/b-1",
+                status = 200,
+                responseBody = """{"id":"b-1","title":"Board","lists":[]}""",
+            )
+            server.register(path = "/api/v1/lists/l-1", status = 200, responseBody = "{}")
+            server.register(path = "/api/v1/cards/c-1", status = 200, responseBody = "{}")
+            server.register(path = "/api/v1/cards/c-2", status = 200, responseBody = "{}")
+
+            val client = HttpKanbnApiClient()
+            val boardResult = client.getBoardDetail(server.baseUrl, "api-123", "b-1")
+            val renameResult = client.renameList(server.baseUrl, "api-123", "l-1", "  New title  ")
+            val moveResult = client.moveCard(server.baseUrl, "api-123", "c-1", "l-9")
+            val deleteResult = client.deleteCard(server.baseUrl, "api-123", "c-2")
+
+            assertTrue(boardResult is BoardsApiResult.Success<*>)
+            assertTrue(renameResult is BoardsApiResult.Success<*>)
+            assertTrue(moveResult is BoardsApiResult.Success<*>)
+            assertTrue(deleteResult is BoardsApiResult.Success<*>)
+
+            val boardRequest = server.findRequest("GET", "/api/v1/boards/b-1")
+            assertNotNull(boardRequest)
+            assertEquals("api-123", boardRequest?.apiKey)
+
+            val renameRequest = server.findRequest("PATCH", "/api/v1/lists/l-1")
+            assertNotNull(renameRequest)
+            assertEquals("{\"name\":\"New title\"}", renameRequest?.body)
+            assertEquals("api-123", renameRequest?.apiKey)
+
+            val moveRequest = server.findRequest("PATCH", "/api/v1/cards/c-1")
+            assertNotNull(moveRequest)
+            assertEquals("{\"listId\":\"l-9\"}", moveRequest?.body)
+            assertEquals("api-123", moveRequest?.apiKey)
+
+            val deleteRequest = server.findRequest("DELETE", "/api/v1/cards/c-2")
+            assertNotNull(deleteRequest)
+            assertEquals("api-123", deleteRequest?.apiKey)
+        }
+    }
+
+    @Test
+    fun serverMessageIsPropagatedWithFallbackWhenMissing() = runTest {
+        TestServer().use { server ->
+            server.register(
+                path = "/api/v1/lists/l-error",
+                status = 400,
+                responseBody = """{"message":"List is locked"}""",
+            )
+            server.register(
+                path = "/api/v1/lists/l-fallback",
+                status = 503,
+                responseBody = "{}",
+            )
+
+            val client = HttpKanbnApiClient()
+            val messageResult = client.renameList(server.baseUrl, "api", "l-error", "Name")
+            val fallbackResult = client.renameList(server.baseUrl, "api", "l-fallback", "Name")
+
+            assertTrue(messageResult is BoardsApiResult.Failure)
+            assertEquals("List is locked", (messageResult as BoardsApiResult.Failure).message)
+            assertTrue(fallbackResult is BoardsApiResult.Failure)
+            assertEquals("Server error: 503", (fallbackResult as BoardsApiResult.Failure).message)
+        }
+    }
+
+    private data class CapturedRequest(
+        val method: String,
+        val path: String,
+        val body: String,
+        val apiKey: String?,
+    )
+
+    private class TestServer : AutoCloseable {
+        private val requests = CopyOnWriteArrayList<CapturedRequest>()
+        private val responses = mutableMapOf<String, Pair<Int, String>>()
+        private val running = AtomicBoolean(true)
+        private val serverSocket = ServerSocket().apply {
+            bind(InetSocketAddress("127.0.0.1", 0))
+        }
+        private val executor = Executors.newSingleThreadExecutor()
+
+        val baseUrl: String = "http://127.0.0.1:${serverSocket.localPort}"
+
+        init {
+            executor.execute {
+                while (running.get()) {
+                    val socket = try {
+                        serverSocket.accept()
+                    } catch (_: Throwable) {
+                        if (!running.get()) {
+                            break
+                        }
+                        continue
+                    }
+                    handle(socket)
+                }
+            }
+        }
+
+        fun register(path: String, status: Int, responseBody: String) {
+            responses["GET $path"] = status to responseBody
+            responses["PATCH $path"] = status to responseBody
+            responses["DELETE $path"] = status to responseBody
+            responses["POST $path"] = status to responseBody
+        }
+
+        fun findRequest(method: String, path: String): CapturedRequest? {
+            return requests.firstOrNull { it.method == method && it.path == path }
+        }
+
+        private fun handle(socket: Socket) {
+            socket.use { s ->
+                s.soTimeout = 3_000
+                val input = BufferedInputStream(s.getInputStream())
+                val output = s.getOutputStream()
+
+                val requestLine = readHttpLine(input).orEmpty()
+                if (requestLine.isBlank()) {
+                    return
+                }
+                val parts = requestLine.split(" ")
+                val method = parts.getOrNull(0).orEmpty()
+                val path = parts.getOrNull(1).orEmpty()
+
+                var apiKey: String? = null
+                var contentLength = 0
+                var methodOverride: String? = null
+                while (true) {
+                    val line = readHttpLine(input).orEmpty()
+                    if (line.isBlank()) {
+                        break
+                    }
+                    val separatorIndex = line.indexOf(':')
+                    if (separatorIndex <= 0) {
+                        continue
+                    }
+                    val headerName = line.substring(0, separatorIndex).trim().lowercase()
+                    val headerValue = line.substring(separatorIndex + 1).trim()
+                    if (headerName == "x-api-key") {
+                        apiKey = headerValue
+                    } else if (headerName == "x-http-method-override") {
+                        methodOverride = headerValue
+                    } else if (headerName == "content-length") {
+                        contentLength = headerValue.toIntOrNull() ?: 0
+                    }
+                }
+
+                val bodyBytes = if (contentLength > 0) ByteArray(contentLength) else ByteArray(0)
+                if (contentLength > 0) {
+                    var total = 0
+                    while (total < contentLength) {
+                        val read = input.read(bodyBytes, total, contentLength - total)
+                        if (read <= 0) {
+                            break
+                        }
+                        total += read
+                    }
+                }
+                val body = String(bodyBytes)
+                val effectiveMethod = methodOverride ?: method
+                requests += CapturedRequest(method = effectiveMethod, path = path, body = body, apiKey = apiKey)
+
+                val response = responses["$effectiveMethod $path"] ?: responses["$method $path"] ?: (404 to "")
+                writeResponse(output, response.first, response.second)
+            }
+        }
+
+        private fun writeResponse(output: OutputStream, status: Int, body: String) {
+            val bytes = body.toByteArray()
+            val reason = when (status) {
+                200 -> "OK"
+                400 -> "Bad Request"
+                404 -> "Not Found"
+                503 -> "Service Unavailable"
+                else -> "Error"
+            }
+            val responseHeaders =
+                "HTTP/1.1 $status $reason\r\n" +
+                    "Content-Type: application/json\r\n" +
+                    "Content-Length: ${bytes.size}\r\n" +
+                    "Connection: close\r\n\r\n"
+            output.write(responseHeaders.toByteArray())
+            output.write(bytes)
+            output.flush()
+        }
+
+        private fun readHttpLine(input: BufferedInputStream): String? {
+            val builder = StringBuilder()
+            while (true) {
+                val next = input.read()
+                if (next == -1) {
+                    return if (builder.isEmpty()) null else builder.toString()
+                }
+                if (next == '\n'.code) {
+                    if (builder.isNotEmpty() && builder.last() == '\r') {
+                        builder.deleteCharAt(builder.length - 1)
+                    }
+                    return builder.toString()
+                }
+                builder.append(next.toChar())
+            }
+        }
+
+        override fun close() {
+            running.set(false)
+            serverSocket.close()
+            executor.shutdownNow()
+            executor.awaitTermination(3, TimeUnit.SECONDS)
+        }
+    }
+}

app/src/test/java/space/hackenslacker/kanbn4droid/app/boards/BoardsRepositoryTest.kt

@@ -8,6 +8,7 @@ import space.hackenslacker.kanbn4droid.app.auth.ApiKeyStore
 import space.hackenslacker.kanbn4droid.app.auth.AuthResult
 import space.hackenslacker.kanbn4droid.app.auth.KanbnApiClient
 import space.hackenslacker.kanbn4droid.app.auth.SessionStore
+import space.hackenslacker.kanbn4droid.app.boarddetail.BoardDetail
 
 class BoardsRepositoryTest {
 
@@ -250,5 +251,31 @@ class BoardsRepositoryTest {
             lastDeletedId = boardId
             return deleteBoardResult
         }
+
+        override suspend fun getBoardDetail(baseUrl: String, apiKey: String, boardId: String): BoardsApiResult<BoardDetail> {
+            return BoardsApiResult.Failure("Not used in this test")
+        }
+
+        override suspend fun renameList(
+            baseUrl: String,
+            apiKey: String,
+            listId: String,
+            newTitle: String,
+        ): BoardsApiResult<Unit> {
+            return BoardsApiResult.Failure("Not used in this test")
+        }
+
+        override suspend fun moveCard(
+            baseUrl: String,
+            apiKey: String,
+            cardId: String,
+            targetListId: String,
+        ): BoardsApiResult<Unit> {
+            return BoardsApiResult.Failure("Not used in this test")
+        }
+
+        override suspend fun deleteCard(baseUrl: String, apiKey: String, cardId: String): BoardsApiResult<Unit> {
+            return BoardsApiResult.Failure("Not used in this test")
+        }
     }
 }

app/src/test/java/space/hackenslacker/kanbn4droid/app/boards/BoardsViewModelTest.kt

@@ -19,6 +19,7 @@ import space.hackenslacker.kanbn4droid.app.auth.ApiKeyStore
 import space.hackenslacker.kanbn4droid.app.auth.AuthResult
 import space.hackenslacker.kanbn4droid.app.auth.KanbnApiClient
 import space.hackenslacker.kanbn4droid.app.auth.SessionStore
+import space.hackenslacker.kanbn4droid.app.boarddetail.BoardDetail
 
 @OptIn(ExperimentalCoroutinesApi::class)
 class BoardsViewModelTest {
@@ -194,5 +195,31 @@ class BoardsViewModelTest {
             lastDeletedId = boardId
             return deleteBoardResult
         }
+
+        override suspend fun getBoardDetail(baseUrl: String, apiKey: String, boardId: String): BoardsApiResult<BoardDetail> {
+            return BoardsApiResult.Failure("Not used in this test")
+        }
+
+        override suspend fun renameList(
+            baseUrl: String,
+            apiKey: String,
+            listId: String,
+            newTitle: String,
+        ): BoardsApiResult<Unit> {
+            return BoardsApiResult.Failure("Not used in this test")
+        }
+
+        override suspend fun moveCard(
+            baseUrl: String,
+            apiKey: String,
+            cardId: String,
+            targetListId: String,
+        ): BoardsApiResult<Unit> {
+            return BoardsApiResult.Failure("Not used in this test")
+        }
+
+        override suspend fun deleteCard(baseUrl: String, apiKey: String, cardId: String): BoardsApiResult<Unit> {
+            return BoardsApiResult.Failure("Not used in this test")
+        }
     }
 }