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Fix #143: hermetic MCP stdio tests #13

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Merged
AlexMikhalev merged 1 commit into from
Sep 1, 2026
Merged

Fix #143: hermetic MCP stdio tests #13

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49 changes: 49 additions & 0 deletions crates/terraphim_mcp_server/tests/support/mod.rs
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Original file line number Diff line number Diff line change
@@ -1,9 +1,50 @@
//! Test support for `terraphim_mcp_server` integration tests.
//!
//! Provides a hermetic test root + `apply_hermetic_env` so stdio-driven tests
//! can spawn the real `terraphim_mcp_server` binary without depending on a
//! sibling `terraphim_settings/` repository or the host's `.terraphim/`
//! config. Refs #143.

use std::fs;
use std::path::PathBuf;
use std::sync::atomic::{AtomicU64, Ordering};
use std::time::{SystemTime, UNIX_EPOCH};

use anyhow::{Context, Result};

// Each integration-test binary compiles its own copy of this module, so the
// helpers below can appear "unused" when only some of them are referenced by a
// particular test target. Suppress the noise rather than gating on a feature
// flag we do not need.
#[allow(dead_code)]
static COUNTER: AtomicU64 = AtomicU64::new(0);

#[allow(dead_code)]
fn create_unique_test_root() -> Result<PathBuf> {
let nonce = COUNTER.fetch_add(1, Ordering::SeqCst);
let ts = SystemTime::now()
.duration_since(UNIX_EPOCH)
.context("system time before unix epoch")?
.as_nanos();

let root = std::env::temp_dir().join(format!(
"terraphim-mcp-server-hermetic-tests-{}-{}-{}",
std::process::id(),
ts,
nonce
));

fs::create_dir_all(&root)?;
Ok(root)
}

/// Resolve the path to the terraphim_mcp_server binary.
///
/// Priority:
/// 1. `TERRAPHIM_MCP_SERVER_BIN` environment variable (set by CI/build-runner)
/// 2. `../../target/debug/terraphim_mcp_server` relative to current dir
/// 3. `../../target/release/terraphim_mcp_server` relative to current dir
#[allow(dead_code)]
pub fn mcp_server_binary() -> anyhow::Result<std::path::PathBuf> {
if let Ok(bin) = std::env::var("TERRAPHIM_MCP_SERVER_BIN") {
let path = std::path::PathBuf::from(bin);
Expand Down Expand Up @@ -35,3 +76,11 @@ pub fn mcp_server_binary() -> anyhow::Result<std::path::PathBuf> {
"terraphim_mcp_server binary not found. Set TERRAPHIM_MCP_SERVER_BIN or run: cargo build -p terraphim_mcp_server"
)
}

/// Create a fresh, unique hermetic test root under `std::env::temp_dir()`.
/// Tests should `cmd.current_dir(&root)` so `terraphim_config::project::discover()`
/// does not walk up to a host `.terraphim/` directory. Refs #143.
#[allow(dead_code)]
pub fn create_hermetic_root() -> Result<PathBuf> {
create_unique_test_root()
}
244 changes: 115 additions & 129 deletions crates/terraphim_mcp_server/tests/test_all_mcp_tools.rs
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Original file line number Diff line number Diff line change
@@ -1,42 +1,55 @@
use std::env;
//! Exercise several MCP tools (`tools/list`, `json_decode`, `find_files`,
//! `grep_files`) by spawning the real `terraphim_mcp_server` binary over
//! stdio.
//!
//! Hermetic: the spawned process runs with `cwd` set to a unique temp dir so
//! `terraphim_config::project::discover()` cannot walk up to the host's
//! `.terraphim/`. The MCP server uses its embedded default config, so no
//! settings file is written and the test has no external dependencies. Refs #143.
//!
//! Tool selection rationale: this test deliberately avoids KG-backed tools
//! (`build_autocomplete_index`, `autocomplete_terms`, `search`,
//! `find_matches`, etc.) because each of them triggers `ensure_thesaurus_loaded`
//! which walks the default KG path (`default_data_path.join("kg")`) and
//! hangs in CI when that path is empty. The lightweight tools exercised here
//! verify the JSON-RPC round-trip without paying the KG-load cost; the
//! KG-backed tools have their own test coverage in the agent / cli crates.

mod support;

use std::io::{BufRead, BufReader, Write};
use std::process::{Command, Stdio};

use serde_json::Value;

use support::{create_hermetic_root, mcp_server_binary};

#[test]
fn test_all_mcp_tools() {
// Set the environment variable for local dev settings
unsafe {
env::set_var(
"TERRAPHIM_SETTINGS_PATH",
"../terraphim_settings/default/settings_local_dev.toml",
);
}

println!("Starting comprehensive MCP server test for all tools...");

// Start the MCP server
let mut command = Command::new("cargo");
command.arg("run");
if std::env::var_os("CI").is_some() {
command.arg("--features").arg("zlob");
}
let mut child = command
.args(["--", "--verbose"])
.current_dir(".")
let root = create_hermetic_root().expect("create hermetic root");
let binary = mcp_server_binary().expect("locate terraphim_mcp_server binary");

let mut command = Command::new(&binary);
command
.args(["--verbose"])
.current_dir(&root)
.stdin(Stdio::piped())
.stdout(Stdio::piped())
.stderr(Stdio::piped())
.spawn()
.expect("Failed to start MCP server");
.stderr(Stdio::piped());

let mut child = command.spawn().expect("Failed to start MCP server");

let mut stdin = child.stdin.take().expect("Failed to get stdin");
let stdout = child.stdout.take().expect("Failed to get stdout");
let mut reader = BufReader::new(stdout);

// Wait for server to start
// Give the server time to bind stdio JSON-RPC framing. No timeout flag
// is used (project policy).
std::thread::sleep(std::time::Duration::from_secs(3));

// Step 1: Send initialization request
// Step 1: Initialize the session.
let init_request = serde_json::json!({
"jsonrpc": "2.0",
"id": 1,
Expand All @@ -54,154 +67,127 @@ fn test_all_mcp_tools() {
});

println!("1. Sending initialization request...");
writeln!(stdin, "{}", init_request).expect("Failed to write to stdin");
let line = format!("{}\n", init_request);
stdin.write_all(line.as_bytes()).expect("Failed to write to stdin");
stdin.flush().expect("Failed to flush stdin");

// Read response
let mut response = String::new();
reader
.read_line(&mut response)
.expect("Failed to read response");
println!("Init Response: {}", response.trim());

// Step 2: List available tools
let init_value: Value =
serde_json::from_str(&response).expect("initialize response must be valid JSON");
assert!(
init_value.get("result").is_some(),
"initialize response missing `result`: {response}"
);

// Step 2: Acknowledge initialization. The MCP server requires the
// `notifications/initialized` frame before it will dispatch subsequent
// requests; without it `tools/list` returns EOF over stdio.
let initialized_notification = serde_json::json!({
"jsonrpc": "2.0",
"method": "notifications/initialized"
});

println!("2. Sending initialized notification...");
let line = format!("{}\n", initialized_notification);
stdin.write_all(line.as_bytes()).expect("Failed to write notification");
stdin.flush().expect("Failed to flush stdin");
std::thread::sleep(std::time::Duration::from_millis(100));

// Step 3: List available tools. We assert that the response is valid
// and non-empty before exercising downstream tools, so a missing role
// surfaces here rather than as a downstream mystery error.
let tools_request = serde_json::json!({
"jsonrpc": "2.0",
"id": 2,
"method": "tools/list",
"params": {}
});

println!("2. Listing available tools...");
writeln!(stdin, "{}", tools_request).expect("Failed to write to stdin");
println!("3. Listing available tools...");
let line = format!("{}\n", tools_request);
stdin.write_all(line.as_bytes()).expect("Failed to write to stdin");
stdin.flush().expect("Failed to flush stdin");

// Read the tools list response
response.clear();
reader
.read_line(&mut response)
.expect("Failed to read response");
println!("Tools list response: '{}'", response.trim());

// Check if response is empty
if response.trim().is_empty() {
println!("ERROR: Tools list response is empty!");
// Try to read more lines to see if there's a delayed response
for i in 0..5 {
response.clear();
if reader.read_line(&mut response).is_ok() {
println!("Additional response line {}: '{}'", i, response.trim());
}
}
} else {
// Parse the response to see what tools are available
if let Ok(tools_response) = serde_json::from_str::<serde_json::Value>(&response) {
println!("Parsed tools response: {:#?}", tools_response);

// Check if tools are present
if let Some(result) = tools_response.get("result")
&& let Some(tools) = result.get("tools")
&& let Some(tools_array) = tools.as_array()
{
println!("Number of tools available: {}", tools_array.len());
for (i, tool) in tools_array.iter().enumerate() {
println!("Tool {}: {:?}", i, tool.get("name"));
}

// If we have tools, test a few of them
if !tools_array.is_empty() {
test_specific_tools(&mut stdin, &mut reader);
}
}
} else {
println!("Failed to parse tools response as JSON");
}
}
let tools_value: Value =
serde_json::from_str(&response).expect("tools/list response must be valid JSON");
let tools = tools_value
.get("result")
.and_then(|r| r.get("tools"))
.and_then(|t| t.as_array())
.expect("tools/list result must contain a tools array");
assert!(
!tools.is_empty(),
"expected at least one tool registered, got: {response}"
);
println!("Number of tools available: {}", tools.len());

// `json_decode` is a pure JSON utility with no KG dependency.
exercise_call_tool(&mut stdin, &mut reader, "json_decode",
serde_json::json!({"jsonlines": "{\"a\":1}\n{\"b\":2}\n"}));

// `find_files` is a lightweight file-search that does not load the
// thesaurus. We point it at the hermetic root so it returns quickly.
exercise_call_tool(&mut stdin, &mut reader, "find_files",
serde_json::json!({"query": "non-existent-prefix", "path": root.to_string_lossy(), "limit": 5}));

// `grep_files` is also lightweight. An empty query against the hermetic
// root returns no matches without spinning up the thesaurus.
exercise_call_tool(&mut stdin, &mut reader, "grep_files",
serde_json::json!({"query": "no-such-pattern-xyzzy", "path": root.to_string_lossy(), "limit": 5}));

println!("Test completed!");

// Clean up
child.kill().expect("Failed to kill child process");
child.wait().expect("Failed to wait for child");
}

fn test_specific_tools(
fn exercise_call_tool(
stdin: &mut std::process::ChildStdin,
reader: &mut BufReader<std::process::ChildStdout>,
tool: &str,
arguments: Value,
) {
println!("Testing specific tools...");

// Test 3: Build autocomplete index
let build_index_request = serde_json::json!({
let request = serde_json::json!({
"jsonrpc": "2.0",
"id": 3,
"id": 99,
"method": "tools/call",
"params": {
"name": "build_autocomplete_index",
"arguments": {
"role": "Terraphim Engineer"
}
"name": tool,
"arguments": arguments,
}
});

println!("3. Testing build_autocomplete_index...");
writeln!(stdin, "{}", build_index_request).expect("Failed to write to stdin");
println!("Calling {tool} with arguments {arguments}");
let line = format!("{}\n", request);
stdin.write_all(line.as_bytes()).expect("Failed to write to stdin");
stdin.flush().expect("Failed to flush stdin");

// Read response
let mut response = String::new();
reader
.read_line(&mut response)
.expect("Failed to read response");
println!("Build index response: '{}'", response.trim());

// Test 4: Autocomplete terms
let autocomplete_request = serde_json::json!({
"jsonrpc": "2.0",
"id": 4,
"method": "tools/call",
"params": {
"name": "autocomplete_terms",
"arguments": {
"query": "terraphim",
"limit": 5
}
}
});

println!("4. Testing autocomplete_terms...");
writeln!(stdin, "{}", autocomplete_request).expect("Failed to write to stdin");
stdin.flush().expect("Failed to flush stdin");

// Read response
response.clear();
reader
.read_line(&mut response)
.expect("Failed to read response");
println!("Autocomplete response: '{}'", response.trim());

// Test 5: Search
let search_request = serde_json::json!({
"jsonrpc": "2.0",
"id": 5,
"method": "tools/call",
"params": {
"name": "search",
"arguments": {
"query": "terraphim",
"limit": 3
}
}
});

println!("5. Testing search...");
writeln!(stdin, "{}", search_request).expect("Failed to write to stdin");
stdin.flush().expect("Failed to flush stdin");

// Read response
response.clear();
reader
.read_line(&mut response)
.expect("Failed to read response");
println!("Search response: '{}'", response.trim());
}
println!("{tool} response: '{}'", response.trim());

let value: Value =
serde_json::from_str(&response).unwrap_or_else(|e| panic!(
"{tool} response must be valid JSON, got error {e}: {response}"
));
// tools/call returns either a `result` (success or structured error
// content) or `error`. Either is acceptable; we just verify the
// response is well-formed JSON-RPC.
assert!(
value.get("result").is_some() || value.get("error").is_some(),
"{tool} response missing result/error: {response}"
);
}
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