When adding/updating tests, optimize for stable, cross-platform correctness and isolation:
- Assert behavior and contracts, not implementation noise. Prefer correctness checks already exercised by existing suites over brittle assertions on internal payload shapes (e.g., exact log field structures), unless that structure is the behavior users rely on.
- Use shared source-of-truth constants. Don’t hardcode package/version strings in tests; import the exported constant and add a dedicated test to ensure it matches the authoritative source (e.g., the core package’s
package.json).
- Keep tests non-leaky. Stub the right layer to prevent never-ending streams, long-running promises, or event listeners from surviving past the test.
- Use framework-native env/mocking helpers. Restore environment state with the matching helper APIs (so tests behave correctly whether variables were originally set or unset).
- Make assertions strict enough to prevent false positives. If required data must cover specific groups/categories (e.g., CLDR plural cardinal categories), ensure tests fail when any required group is missing—not just when the happy-path keys exist.
Example (pattern):
import { SKILLS_CLI_PACKAGE } from "@cline/core";
import { describe, expect, it, vi } from "vitest";
it("builds args using exported constants", () => {
expect(buildSkillsArgs(["list"]))
.toEqual(["-y", SKILLS_CLI_PACKAGE, "list"]);
});
describe("env-dependent command", () => {
it("writes config using stubbed env", async () => {
vi.stubEnv({ CLINE_MCP_SETTINGS_PATH: "/tmp/settings.json" });
try {
const code = await runMcpInstallCommand(/* ... */);
expect(code).toBe(0);
} finally {
vi.unstubAllEnvs();
}
});
});
Apply this as a quick checklist for every test change: (1) contract-based assertions, (2) strict correctness coverage, (3) no leaks, (4) safe env/mocking, (5) avoid brittle internals.