Add an integration test for error recovery

spec/lrama/integration_spec.rb

@@ -151,4 +151,47 @@ def test_rules(rules, input, expected, command_args: [], debug: false)
  Rules
  end
  end
+
+ # TODO: Add test case for "(1+2"
+ describe "error_recovery" do
+ it "returns 6 for '(1+)'" do
+ # (1+) #=> 101
+ # '100' is complemented
+ input = [
+ %w['('],
+ %w[NUM val 1],
+ %w['+'],
+ %w[')'],
+ ]
+
+ test_rules(<<~Rules, input, "=> 101", command_args: %W[-e])
+ %union {
+ int val;
+ }
+ %token <val> NUM
+ %type <val> expr
+ %left '+' '-'
+ %left '*' '/'
+
+ %error-token {
+ $$ = 100;
+ } NUM
+
+ %%
+
+ program : { (void)yynerrs; }
+ | expr { printf("=> %d", $1); }
+ ;
+ expr : NUM
+ | expr '+' expr { $$ = $1 + $3; }
+ | expr '-' expr { $$ = $1 - $3; }
+ | expr '*' expr { $$ = $1 * $3; }
+ | expr '/' expr { $$ = $1 / $3; }
+ | '(' expr ')' { $$ = $2; }
+ ;
+
+ %%
+ Rules
+ end
+ end
 end