Add support for testing JSON serialization of the mcp API (#45)

* Add kotest-assertions-json dependency + ToolSerializationTest

* ToolSerializationTest update

Author: morisil

build.gradle.kts

@@ -219,6 +219,7 @@ kotlin {
                 implementation(libs.ktor.server.test.host)
                 implementation(libs.kotlinx.coroutines.test)
                 implementation(libs.kotlinx.coroutines.debug)
+                implementation(libs.kotest.assertions.json)
             }
         }
 

gradle/libs.versions.toml

@@ -13,6 +13,7 @@ logging = "7.0.0"
 jreleaser = "1.15.0"
 binaryCompatibilityValidatorPlugin = "0.17.0"
 slf4j = "2.0.16"
+kotest = "5.9.1"
 
 [libraries]
 # Kotlinx libraries
@@ -32,8 +33,7 @@ kotlinx-coroutines-debug = { group = "org.jetbrains.kotlinx", name = "kotlinx-co
 ktor-server-test-host = { group = "io.ktor", name = "ktor-server-test-host", version.ref = "ktor" }
 mockk = { group = "io.mockk", name = "mockk", version.ref = "mockk" }
 slf4j-simple = { group = "org.slf4j", name = "slf4j-simple", version.ref = "slf4j" }
-
-
+kotest-assertions-json = { group = "io.kotest", name = "kotest-assertions-json", version.ref = "kotest" }
 
 [plugins]
 kotlin-multiplatform = { id = "org.jetbrains.kotlin.multiplatform", version.ref = "kotlin" }

src/commonTest/kotlin/ToolSerializationTest.kt

@@ -0,0 +1,57 @@
+package io.modelcontextprotocol.kotlin.sdk
+
+import io.kotest.assertions.json.shouldEqualJson
+import io.modelcontextprotocol.kotlin.sdk.shared.McpJson
+import kotlinx.serialization.encodeToString
+import kotlinx.serialization.json.JsonPrimitive
+import kotlinx.serialization.json.buildJsonObject
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class ToolSerializationTest {
+
+    // see https://docs.anthropic.com/en/docs/build-with-claude/tool-use
+    /* language=json */
+    private val getWeatherToolJson = """
+        {
+          "name": "get_weather",
+          "description": "Get the current weather in a given location",
+          "inputSchema": {
+            "type": "object",
+            "properties": {
+              "location": {
+                "type": "string",
+                "description": "The city and state, e.g. San Francisco, CA"
+              }
+            },
+            "required": ["location"]
+          }
+        }
+    """.trimIndent()
+
+    val getWeatherTool = Tool(
+        name = "get_weather",
+        description = "Get the current weather in a given location",
+        inputSchema = Tool.Input(
+            properties = buildJsonObject {
+                put("location", buildJsonObject {
+                    put("type", JsonPrimitive("string"))
+                    put("description", JsonPrimitive("The city and state, e.g. San Francisco, CA"))
+                })
+            },
+            required = listOf("location")
+        )
+    )
+
+    @Test
+    fun `should serialize get_weather tool`() {
+        McpJson.encodeToString(getWeatherTool) shouldEqualJson getWeatherToolJson
+    }
+
+    @Test
+    fun `should deserialize get_weather tool`() {
+        val tool = McpJson.decodeFromString<Tool>(getWeatherToolJson)
+        assertEquals(expected = getWeatherTool, actual = tool)
+    }
+
+}