add a script for copying schema information from python to typescript

There was no script for updating typescript schema information after
a python-based document migration. Moving one in here, along with its
test. Tweaked the code slightly to work with grist-core's directory
structure. Also fixed a formatting error in mocha calls that was resulting
in some root tests not running.

test/server/generateInitialDocSql.ts

@@ -0,0 +1,41 @@
+import { getAppRoot } from 'app/server/lib/places';
+import { createTmpDir } from 'test/server/docTools';
+import * as testUtils from 'test/server/testUtils';
+
+import { assert } from 'chai';
+import * as childProcess from 'child_process';
+import * as fse from 'fs-extra';
+import * as path from 'path';
+import * as util from 'util';
+
+const execFile = util.promisify(childProcess.execFile);
+
+describe('generateInitialDocSql', function() {
+  this.timeout(10000);
+
+  let tmpDir: string;
+
+  testUtils.setTmpLogLevel('fatal');
+
+  before(async function() {
+    tmpDir = await createTmpDir();
+  });
+
+  it('confirms schema and sql files are up to date (run "./build schema" on failure)', async function() {
+    let root = getAppRoot();
+    if (await fse.pathExists(path.join(root, 'core'))) {
+      root = path.join(root, 'core');
+    }
+    const newSchemaTs = path.join(tmpDir, 'schema.ts');
+    const newSqlTs = path.join(tmpDir, 'sql.ts');
+    const currentSchemaTs = path.join(root, 'app/common/schema.ts');
+    const currentSqlTs = path.join(root, 'app/server/lib/initialDocSql.ts');
+    await execFile(path.join(getAppRoot(), 'buildtools/update_schema.sh'), [
+      newSchemaTs, newSqlTs,
+    ], { env: process.env });
+    assert.equal((await fse.readFile(newSchemaTs)).toString(),
+                 (await fse.readFile(currentSchemaTs)).toString());
+    assert.equal((await fse.readFile(newSqlTs)).toString(),
+                 (await fse.readFile(currentSqlTs)).toString());
+  });
+});