test: document report helper module

PR-URL: #27434
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

test/common/README.md

@@ -14,6 +14,7 @@ This directory contains modules used to test the Node.js implementation.
 * [Heap dump checker module](#heap-dump-checker-module)
 * [HTTP2 module](#http2-module)
 * [Internet module](#internet-module)
+* [Report module](#report-module)
 * [tick module](#tick-module)
 * [tmpdir module](#tmpdir-module)
 * [WPT module](#wpt-module)
@@ -796,6 +797,33 @@ a full `setImmediate()` invocation passes.
 `listener` is an object to make it easier to use a closure; the target object
 should not be in scope when `listener.ongc()` is created.
 
+## Report Module
+
+The `report` module provides helper functions for testing diagnostic reporting
+functionality.
+
+### findReports(pid, dir)
+
+* `pid` [<number>] Process ID to retrieve diagnostic report files for.
+* `dir` [<string>] Directory to search for diagnostic report files.
+* return [<Array>]
+
+Returns an array of diagnotic report file names found in `dir`. The files should
+have been generated by a process whose PID matches `pid`.
+
+### validate(report)
+
+* `report` [<string>] Diagnostic report file name to validate.
+
+Validates the schema of a diagnostic report file whose path is specified in
+`report`. If the report fails validation, an exception is thrown.
+
+### validateContent(data)
+
+* `data` [<string>] Contents of a diagnostic report file.
+
+Validates the schema of a diagnostic report whose content is specified in
+`data`. If the report fails validation, an exception is thrown.
 
 ## tick Module