coyote/docs/testing/notes/ITERATION-5-NOTES.md

Iteration 5 — Test Implementation Notes

Plan file addressed

docs/testing/plans/05-mcp-lifecycle.md

Tests created

src/config/mcp_factory.rs (12 new tests)

Test name	What it verifies
key_from_stdio_spec_captures_command_args_env	McpServerKey extracts command, args, env from stdio spec
key_from_stdio_spec_sorts_args_and_env	Args and env are sorted for deterministic key hashing
key_from_stdio_spec_defaults_empty_when_none	None args/env default to empty vecs
key_from_remote_http_spec	Http transport key captures url and transport type
key_from_remote_sse_spec_with_sorted_headers	SSE headers sorted for deterministic keys
key_equality_same_spec_produces_equal_keys	Same spec → equal keys (sharing contract)
key_inequality_different_names	Different server names → different keys
key_inequality_different_commands	Different commands → different keys (isolation contract)
key_env_bool_and_int_coerce_to_string	JsonField::Bool/Int coerced to String in key
factory_try_get_active_returns_none_when_empty	Empty factory returns None
factory_try_get_active_returns_none_for_unknown_key	Unknown key returns None
factory_default_has_empty_active_map	Default factory has empty internal map

src/config/tool_scope.rs (6 new tests)

Test name	What it verifies
mcp_runtime_new_is_empty	New McpRuntime has no servers
mcp_runtime_default_is_empty	Default McpRuntime is empty
mcp_runtime_get_returns_none_for_missing_server	get() on nonexistent server returns None
tool_scope_default_has_empty_mcp_runtime	Default ToolScope has empty MCP runtime
tool_scope_default_has_empty_functions	Default ToolScope has no functions
tool_scope_default_tracker_has_no_loops	Default ToolScope tracker detects no loops

src/mcp/mod.rs (30 new tests)

Test name	What it verifies
validate_stdio_with_command_succeeds	Valid stdio spec passes
validate_stdio_missing_command_fails	Stdio without command is rejected
validate_stdio_with_url_fails	Stdio with url (remote field) is rejected
validate_stdio_with_headers_fails	Stdio with headers (remote field) is rejected
validate_http_with_url_succeeds	Valid http spec passes
validate_http_missing_url_fails	Http without url is rejected
validate_http_with_command_fails	Http with command (stdio field) is rejected
validate_http_with_args_fails	Http with args (stdio field) is rejected
validate_http_with_cwd_fails	Http with cwd (stdio field) is rejected
validate_sse_with_url_succeeds	Valid SSE spec passes
validate_sse_missing_url_fails	SSE without url is rejected
is_remote_true_for_http_and_sse	Http and SSE are remote transports
is_remote_false_for_stdio	Stdio is not remote
deserialize_stdio_server_from_json	Full stdio spec from JSON
deserialize_http_server_from_json	Http spec with headers from JSON
deserialize_env_with_mixed_types	Env with String, Bool, Int values
deserialize_multiple_servers	Multiple server entries parsed
deserialize_empty_servers_map	Empty mcpServers map parsed
deserialize_server_with_cwd	cwd field parsed correctly
resolve_all_returns_all_configured_servers	"all" resolves to all config keys
resolve_comma_separated_returns_matching_servers	Comma-separated list filters correctly
resolve_single_server_name	Single name resolved
resolve_none_returns_empty	None enabled → empty list
resolve_no_config_returns_empty	No config → empty list
resolve_nonexistent_server_filtered_out	Unknown names silently filtered
resolve_all_nonexistent_returns_empty	All unknown → empty list
resolve_trims_whitespace	Whitespace in comma list trimmed
registry_default_is_empty	Default registry: empty, no config, no log
registry_with_config_reports_config	Config accessor works
meta_function_prefixes_are_correct	mcp_invoke/search/describe prefixes

src/config/request_context.rs (6 new tests)

Test name	What it verifies
rebuild_tool_scope_mcp_disabled_skips_servers	mcp_server_support=false → empty runtime
rebuild_tool_scope_no_enabled_servers_yields_empty_runtime	None enabled → empty runtime
rebuild_tool_scope_no_mcp_config_yields_empty_runtime	No mcp_config → empty runtime
rebuild_tool_scope_preserves_tool_tracker	Tracker survives rebuild
rebuild_tool_scope_repl_mode_appends_user_interaction_functions	REPL adds user__ functions
rebuild_tool_scope_cmd_mode_no_user_interaction_functions	CMD skips user__ functions

Total: 54 new tests (176 total in suite)

Bugs discovered

None.

Observations for future iterations

1. ConnectedServer untestable without subprocess: ConnectedServer (= RunningService<RoleClient, ()>) cannot be constructed without a real MCP server subprocess. This blocks unit testing for:

   • McpFactory.acquire() full flow (spawn + insert + Weak sharing)
   • McpRuntime.insert/get with real handles
   • McpRuntime.search/describe/invoke (need live tool catalog)
   • All scope transition tests (role/session/agent MCP start/stop)

   These require integration tests with a mock MCP server binary (e.g., a simple echo server). Recommended for a dedicated integration test iteration.

2. McpServerKey sorting guarantees sharing correctness: The sorting of args, env, and headers in McpServerKey::from_spec is critical — without it, HashMap key equality would be non-deterministic. Tests verify this explicitly.

3. rebuild_tool_scope has 3 guard clauses that prevent server acquisition: mcp_server_support=false, mcp_config=None, enabled_mcp_servers=None. All three paths tested.

4. REPL vs CMD mode differs in user interaction functions: The rebuild_tool_scope method conditionally appends user__* functions only in REPL mode. Tested both paths.

5. McpServer::validate enforces strict transport/field separation: Stdio servers cannot have url/headers, remote servers cannot have command/args/cwd. This prevents misconfiguration. All cross-field conflict cases tested.

6. McpRegistry.resolve_server_ids is private but tested via #[cfg(test)] in the same module. It's the core of server ID resolution for "all", comma-separated, and empty cases.

Next iteration

Plan file 06: Tool Evaluation — eval_tool_calls, ToolCall dispatch, tool handlers, MCP tool invocation chain (mcp__search, mcp__describe, mcp__invoke).