Merge pull request #308 from hildjj/dash-stdin-test

Make `-T -` read a test from stdin.

Author: hildjj

CHANGELOG.md

@@ -38,6 +38,7 @@ Released: TBD
   editors, from @Mingun
 - [#299](https://github.com/peggyjs/peggy/issues/299) Add example grammar for a
   [SemVer.org](https://semver.org) semantic version string, from @dselman
+- [#308](https://github.com/peggyjs/peggy/pull/308) Add support for reading test data from stdin using `-T -`, from @hildjj.
 
 ### Bug Fixes
 

bin/peggy-cli.js

@@ -191,7 +191,7 @@ class PeggyCLI extends Command {
       )
       .addOption(new Option(
         "-T, --test-file <filename>",
-        "Test the parser with the contents of the given file, outputting the result of running the parser instead of the parser itself. If the input to be tested is not parsed, the CLI will exit with code 2"
+        "Test the parser with the contents of the given file, outputting the result of running the parser instead of the parser itself. If the input to be tested is not parsed, the CLI will exit with code 2. A filename of '-' will read from stdin."
       ).conflicts("test"))
       .option("--trace", "Enable tracing in generated parser", false)
       .addOption(
@@ -548,9 +548,13 @@ class PeggyCLI extends Command {
     });
   }
 
-  test(source) {
+  async test(source) {
     if (this.testFile) {
-      this.testText = fs.readFileSync(this.testFile, "utf8");
+      if (this.testFile === "-") {
+        this.testText = await readStream(this.std.in);
+      } else {
+        this.testText = fs.readFileSync(this.testFile, "utf8");
+      }
     }
     if (typeof this.testText === "string") {
       this.verbose("TEST TEXT:", this.testText);
@@ -654,7 +658,7 @@ class PeggyCLI extends Command {
 
         exitCode = 2;
         this.verbose("CLI", errorText = "running test");
-        this.test(mappedSource);
+        await this.test(mappedSource);
       }
     } catch (error) {
       // Will either exit or throw.

test/cli/run.spec.ts

@@ -370,7 +370,8 @@ Options:
                                    given file, outputting the result of running
                                    the parser instead of the parser itself. If
                                    the input to be tested is not parsed, the
-                                   CLI will exit with code 2
+                                   CLI will exit with code 2. A filename of '-'
+                                   will read from stdin.
   --trace                          Enable tracing in generated parser (default:
                                    false)
   -h, --help                       display help for command
@@ -1040,6 +1041,12 @@ bar = '2'
       expected: /name: 'peggy',$/m, // Output is JS, not JSON
     });
 
+    await exec({
+      args: [grammarFile, "-T", "-"],
+      stdin: '{"foo": null}',
+      expected: "{ foo: null }\n", // Still JS, not JSON
+    });
+
     await exec({
       args: ["-T", "____ERROR____FILE_DOES_NOT_EXIST.js", grammarFile],
       errorCode: "peggy.cli",