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

* Add kotest-assertions-json dependency + ToolSerializationTest

* ToolSerializationTest update

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)
+    }
+
+}