test(NODE-3211): convert gridfs tests to unified test format

src/gridfs/download.ts

@@ -56,15 +56,41 @@ export interface GridFSFile {
 
 /** @internal */
 export interface GridFSBucketReadStreamPrivate {
+  /**
+   * The running total number of bytes read from the chunks collection.
+   */
   bytesRead: number;
+  /**
+   * The number of bytes to remove from the last chunk read in the file.  This is non-zero
+   * if `end` is not equal to the length of the document and `end` is not a multiple
+   * of the chunkSize.
+   */
   bytesToTrim: number;
+
+  /**
+   * The number of bytes to remove from the first chunk read in the file.  This is non-zero
+   * if `start` is not equal to the 0  and `start` is not a multiple
+   * of the chunkSize.
+   */
   bytesToSkip: number;
+
+  files: Collection<GridFSFile>;
   chunks: Collection<GridFSChunk>;
   cursor?: FindCursor<GridFSChunk>;
+
+  /** The running total number of chunks read from the chunks collection. */
   expected: number;
-  files: Collection<GridFSFile>;
+
+  /**
+   * The filter used to search in the _files_ collection (i.e., `{ _id: <> }`)
+   * This is not the same filter used when reading chunks from the chunks collection.
+   */
   filter: Document;
+
+  /** Indicates whether or not download has started. */
   init: boolean;
+
+  /** The expected number of chunks to read, calculated from start, end, chunkSize and file length. */
   expectedEnd: number;
   file?: GridFSFile;
   options: {

test/integration/gridfs/gridfs.spec.test.ts

@@ -0,0 +1,8 @@
+import { loadSpecTests } from '../../spec';
+import { runUnifiedSuite } from '../../tools/unified-spec-runner/runner';
+
+describe('GridFS Unified Tests', function () {
+  runUnifiedSuite(loadSpecTests('gridfs'), ({ description }) => {
+    return description === 'download when final chunk is missing' ? `TODO(NODE-6279): throw a missing chunk error when last chunk is missing` : false;
+  });
+});

test/spec/gridfs/README.md

@@ -0,0 +1,28 @@
+# GridFS Tests
+
+______________________________________________________________________
+
+## Introduction
+
+The YAML and JSON files in this directory are platform-independent tests meant to exercise a driver's implementation of
+GridFS. These tests utilize the [Unified Test Format](../../unified-test-format/unified-test-format.md).
+
+## Conventions for Expressing Binary Data
+
+The unified test format allows binary stream data to be expressed and matched with `$$hexBytes` (for uploads) and
+`$$matchesHexBytes` (for downloads), respectively; however, those operators are not supported in all contexts, such as
+`insertData` and `outcome`. When binary data must be expressed as a base64-encoded string
+([Extended JSON](../../extended-json.md) for a BSON binary type), the test SHOULD include a comment noting the
+equivalent value in hexadecimal for human-readability. For example:
+
+```yaml
+data: { $binary: { base64: "ESIzRA==", subType: "00" } } # hex 11223344
+```
+
+Creating the base64-encoded string for a sequence of hexadecimal bytes is left as an exercise to the developer. Consider
+the following PHP one-liner:
+
+```shell-session
+$ php -r 'echo base64_encode(hex2bin('11223344')), "\n";'
+ESIzRA==
+```