@augment-vir/test
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A universal testing suite that works with Mocha style test runners _and_ Node.js's built-in test runner.
79 lines (78 loc) • 3.15 kB
JavaScript
import { check } from '@augment-vir/assert';
import { extractErrorMessage, getOrSet, RuntimeEnv } from '@augment-vir/common';
import { extractTestName, isTestContext, } from './universal-test-context.js';
/**
* An error that is thrown from {@link assertSnapshot} when the snapshot comparison fails due to the
* snapshot expectation file simply not existing.
*
* @category Test : Util
* @category Package : @augment-vir/test
* @package [`@augment-vir/test`](https://www.npmjs.com/package/@augment-vir/test)
*/
export class SnapshotFileMissingError extends Error {
constructor(testName) {
super(`Missing snapshot file for test '${testName}'.\n\nRun tests in update mode to create the snapshot file.`);
}
}
/**
* Assert that the given snapshot data matches already-saved snapshot file's expectations. Note that
* the given data will be serialized into a JSON string if it is not already a string. This works in
* both Node and web tests.
*
* Web tests require a web-test-runner config with the `snapshotPlugin` plugin from
* `@virmator/test/dist/web-snapshot-plugin/web-snapshot-plugin.js` in order to work.
*
* @category Test
* @category Package : @augment-vir/test
* @package [`@augment-vir/test`](https://www.npmjs.com/package/@augment-vir/test)
*/
export async function assertSnapshot(testContext, data) {
const { snapshotName, testName } = getTestName(testContext);
const serializedData = check.isString(data) ? data : JSON.stringify(data);
if (isTestContext(testContext, RuntimeEnv.Node)) {
try {
testContext.assert.snapshot(serializedData);
}
catch (error) {
if (extractErrorMessage(error).includes('Cannot read snapshot file')) {
throw new SnapshotFileMissingError(testName);
}
else {
throw error;
}
}
}
else {
const { SnapshotCommand } = await import('@virmator/test/dist/web-snapshot-plugin/snapshot-payload.js');
const { executeServerCommand } = await import('@web/test-runner-commands');
const result = await executeServerCommand(SnapshotCommand.CompareSnapshot, {
content: serializedData,
name: snapshotName,
});
if (!result.updated) {
if (!result.exists) {
throw new SnapshotFileMissingError(testName);
}
else if (!result.matches) {
throw new Error(`Snapshot mismatch at '${testName}':\n\nActual: ${serializedData}\n\nExpected: ${result.savedSnapshot}\n`);
}
}
}
}
function getTestName(testContext) {
const testName = extractTestName(testContext);
const snapshotCountObject = getOrSet(testContext, 'snapshotCount', () => {
return {};
});
const currentSnapshotCount = getOrSet(snapshotCountObject, testName, () => 0);
const newSnapshotCount = currentSnapshotCount + 1;
snapshotCountObject[testName] = newSnapshotCount;
const snapshotName = [
testName,
newSnapshotCount,
].join(' ');
return {
snapshotName,
testName,
};
}