Add new test to help @glimmer/syntax not accidentally remove public API

packages/@glimmer/syntax/test/public-api-test.ts

@@ -0,0 +1,37 @@
+import * as syntax from '@glimmer/syntax';
+
+QUnit.module('[glimmer-syntax] Public API is unchanged');
+
+QUnit.test('exports are not accidentally removed', function(assert) {
+  assert.ok(syntax.print);
+  assert.ok(syntax.sortByLoc);
+  assert.ok(syntax.getTemplateLocals);
+  assert.ok(syntax.isKeyword);
+  assert.ok(syntax.KEYWORDS_TYPES);
+  assert.ok(syntax.src);
+  assert.ok(syntax.preprocess);
+  assert.ok(syntax.hasSpan);
+  assert.ok(syntax.loc);
+  assert.ok(syntax.maybeLoc);
+  assert.ok(syntax.SpanList);
+  assert.ok(syntax.BlockSymbolTable);
+  assert.ok(syntax.ProgramSymbolTable);
+  assert.ok(syntax.SymbolTable);
+  assert.ok(syntax.generateSyntaxError);
+  assert.ok(syntax.cannotRemoveNode);
+  assert.ok(syntax.cannotReplaceNode);
+  assert.ok(syntax.WalkerPath);
+  assert.ok(syntax.traverse);
+  assert.ok(syntax.Walker);
+  assert.ok(syntax.ASTv1);
+  assert.ok(syntax.builders);
+  assert.ok(syntax.visitorKeys);
+  assert.ok(syntax.ASTv2);
+  assert.ok(syntax.normalize);
+  assert.ok(syntax.node);
+  // deprecated
+  assert.ok(syntax.Path);
+  // deprecated
+  assert.ok(syntax.AST);
+
+});