feat!: add mcp conformance test infra (#585); add SSE reconnection with retry support (#596) (#585)

Adds a comprehensive conformance test suite for the Kotlin MCP SDK,
covering core protocol operations, tool calls, elicitation, resources,
prompts, and 20 OAuth/auth scenarios

- Conformance server and client implementations
- OAuth/auth test scenarios: JWT, authorization code flow, client
credentials, PKCE, scope handling, cross-app access, client registration
- CI workflow
- Baseline file for tracking expected failures
- Shell script

fixes:
- #592
- #593
- #596


## Remaining known failures (tracked issues, will be fixed directly in
`main`)

- [x] `tools-call-with-logging`, `tools-call-with-progress`,
`tools-call-sampling`, `tools-call-elicitation`,
`elicitation-sep1034-defaults`-  see #599,
- [x] `elicitation-sep1330-enums` - #587 #600
- [x] `initialize` - #588 
- [x] `tools_call`, `auth/scope-step-up`, `auth/scope-retry-limit` -
#589
- [ ] `elicitation-sep1034-client-defaults` - #414 
- [x] `sse-retry` - #590 
- [ ] `resources-templates-read` - #591 

## Breaking Changes
from #596 
- `StreamableHttpClientTransport` and
`mcpStreamableHttp`/`mcpStreamableHttpTransport`: old constructors
accepting `Duration` timeout are now `@Deprecated` — use the new
overloads with `ReconnectionOptions` instead
- `StreamableHttpClientTransport.close()` no longer calls
`terminateSession()` automatically

## Types of changes
- [x] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [x] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update

## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed

---------

Co-authored-by: Konstantin Pavlov <1517853+kpavlov@users.noreply.github.com>

conformance-test/run-conformance.sh

@@ -0,0 +1,194 @@
+#!/bin/bash
+# Script to run MCP conformance tests for the Kotlin SDK.
+#
+# Usage: ./conformance-test/run-conformance.sh <command> [extra-args...]
+# Commands: server | client | client-auth | all
+
+set -uo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" || exit 1; pwd)"
+PROJECT_ROOT="$(cd "$SCRIPT_DIR/.." || exit 1; pwd)"
+
+CONFORMANCE_VERSION="0.1.15"
+PORT="${MCP_PORT:-3001}"
+SERVER_URL="http://localhost:${PORT}/mcp"
+RESULTS_DIR="$SCRIPT_DIR/results"
+SERVER_DIST="$SCRIPT_DIR/build/install/conformance-test/bin/conformance-test"
+CLIENT_DIST="$SCRIPT_DIR/build/install/conformance-test/bin/conformance-client"
+
+SERVER_PID=""
+
+# shellcheck disable=SC2317
+cleanup() {
+    if [ -n "$SERVER_PID" ] && kill -0 "$SERVER_PID" 2>/dev/null; then
+        echo "Stopping server (PID: $SERVER_PID)..."
+        kill "$SERVER_PID" 2>/dev/null || true
+        wait "$SERVER_PID" 2>/dev/null || true
+    fi
+}
+trap cleanup EXIT
+
+build() {
+    echo "Building conformance-test distributions..."
+    cd "$PROJECT_ROOT" || return 1
+    ./gradlew :conformance-test:installDist --quiet
+    cd "$SCRIPT_DIR" || return 1
+    echo "Build complete."
+}
+
+start_server() {
+    echo "Starting conformance server on port $PORT..."
+    MCP_PORT="$PORT" "$SERVER_DIST" &
+    SERVER_PID=$!
+
+    echo "Waiting for server to be ready..."
+    local retries=0
+    local max_retries=30
+    while ! curl -sf "$SERVER_URL" > /dev/null 2>&1; do
+        retries=$((retries + 1))
+        if [ "$retries" -ge "$max_retries" ]; then
+            echo "ERROR: Server failed to start after $max_retries attempts"
+            return 1
+        fi
+        sleep 0.5
+    done
+    echo "Server is ready (PID: $SERVER_PID)."
+}
+
+stop_server() {
+    if [ -n "$SERVER_PID" ] && kill -0 "$SERVER_PID" 2>/dev/null; then
+        echo "Stopping server (PID: $SERVER_PID)..."
+        kill "$SERVER_PID" 2>/dev/null || true
+        wait "$SERVER_PID" 2>/dev/null || true
+        SERVER_PID=""
+    fi
+}
+
+run_list_scenarios() {
+    local output_dir="$RESULTS_DIR/list"
+    mkdir -p "$output_dir"
+    echo ""
+    echo "=========================================="
+    echo "  List Available Scenarios"
+    echo "=========================================="
+    local rc=0
+    npx "@modelcontextprotocol/conformance@$CONFORMANCE_VERSION" list \
+        "$@" > "$output_dir/scenarios.txt" || rc=$?
+
+    cat "$output_dir/scenarios.txt"
+    return $rc
+}
+
+run_server_suite() {
+    local output_dir="$RESULTS_DIR/server"
+    mkdir -p "$output_dir"
+    echo ""
+    echo "=========================================="
+    echo "  Running SERVER conformance tests"
+    echo "=========================================="
+    start_server || return 1
+    local rc=0
+    npx "@modelcontextprotocol/conformance@$CONFORMANCE_VERSION" server \
+        --url "$SERVER_URL" \
+        --output-dir "$output_dir" \
+        --expected-failures "$SCRIPT_DIR/conformance-baseline.yml" \
+        "$@" || rc=$?
+    stop_server
+    return $rc
+}
+
+run_client_suite() {
+    local output_dir="$RESULTS_DIR/client"
+    mkdir -p "$output_dir"
+    echo ""
+    echo "=========================================="
+    echo "  Running CLIENT conformance tests"
+    echo "=========================================="
+    local scenarios=("initialize" "tools_call" "elicitation-sep1034-client-defaults" "sse-retry")
+    local rc=0
+    for scenario in "${scenarios[@]}"; do
+        npx "@modelcontextprotocol/conformance@$CONFORMANCE_VERSION" client \
+            --command "$CLIENT_DIST" \
+            --scenario "$scenario" \
+            --output-dir "$output_dir" \
+            --expected-failures "$SCRIPT_DIR/conformance-baseline.yml" \
+            "$@" || rc=$?
+    done
+    return $rc
+}
+
+run_client_auth_suite() {
+    local output_dir="$RESULTS_DIR/client-auth"
+    mkdir -p "$output_dir"
+    echo ""
+    echo "=========================================="
+    echo "  Running CLIENT (auth) conformance tests"
+    echo "=========================================="
+    local rc=0
+    npx "@modelcontextprotocol/conformance@$CONFORMANCE_VERSION" client \
+        --command "$CLIENT_DIST" \
+        --suite auth \
+        --output-dir "$output_dir" \
+        --expected-failures "$SCRIPT_DIR/conformance-baseline.yml" \
+        "$@" || rc=$?
+
+    local extra_scenarios=("auth/client-credentials-jwt" "auth/client-credentials-basic" "auth/cross-app-access-complete-flow")
+    for scenario in "${extra_scenarios[@]}"; do
+        npx "@modelcontextprotocol/conformance@$CONFORMANCE_VERSION" client \
+            --command "$CLIENT_DIST" \
+            --scenario "$scenario" \
+            --output-dir "$output_dir" \
+            --expected-failures "$SCRIPT_DIR/conformance-baseline.yml" \
+            "$@" || rc=$?
+    done
+    return $rc
+}
+
+# ============================================================================
+# Main
+# ============================================================================
+
+COMMAND="${1:-}"
+shift 2>/dev/null || true
+
+if [ -z "$COMMAND" ]; then
+    echo "Usage: $0 <command> [extra-args...]"
+    echo "Commands: list | server | client | client-auth | all"
+    exit 1
+fi
+
+build
+
+EXIT_CODE=0
+
+case "$COMMAND" in
+    list)
+        run_list_scenarios "$@" || EXIT_CODE=1
+        ;;
+    server)
+        run_server_suite "$@" || EXIT_CODE=1
+        ;;
+    client)
+        run_client_suite "$@" || EXIT_CODE=1
+        ;;
+    client-auth)
+        run_client_auth_suite "$@" || EXIT_CODE=1
+        ;;
+    all)
+        run_server_suite "$@" || EXIT_CODE=1
+        run_client_suite "$@" || EXIT_CODE=1
+        run_client_auth_suite "$@" || EXIT_CODE=1
+        ;;
+    *)
+        echo "Unknown command: $COMMAND"
+        echo "Commands: list | server | client | client-auth | all"
+        exit 1
+        ;;
+esac
+
+echo ""
+echo "=========================================="
+echo "  Results saved to: $RESULTS_DIR"
+echo "=========================================="
+
+exit $EXIT_CODE