Move db mocking into factory file

So we can re-use it.

Author: elenatanasoiu

extensions/ql-vscode/test/factories/databases/databases.ts

@@ -0,0 +1,46 @@
+import { join } from "path";
+import { Uri } from "vscode";
+import {
+  DatabaseContents,
+  DatabaseItemImpl,
+  FullDatabaseOptions,
+} from "../../../src/local-databases";
+import { DirResult } from "tmp";
+
+export function mockDbOptions(): FullDatabaseOptions {
+  return {
+    dateAdded: 123,
+    ignoreSourceArchive: false,
+    language: "",
+  };
+}
+
+export function createMockDB(
+  dir: DirResult,
+  dbOptions = mockDbOptions(),
+  // source archive location must be a real(-ish) location since
+  // tests will add this to the workspace location
+  sourceArchiveUri?: Uri,
+  databaseUri?: Uri,
+): DatabaseItemImpl {
+  sourceArchiveUri = sourceArchiveUri || sourceLocationUri(dir);
+  databaseUri = databaseUri || dbLocationUri(dir);
+
+  return new DatabaseItemImpl(
+    databaseUri,
+    {
+      sourceArchiveUri,
+      datasetUri: databaseUri,
+    } as DatabaseContents,
+    dbOptions,
+    () => void 0,
+  );
+}
+
+export function sourceLocationUri(dir: DirResult) {
+  return Uri.file(join(dir.name, "src.zip"));
+}
+
+export function dbLocationUri(dir: DirResult) {
+  return Uri.file(join(dir.name, "db"));
+}