From bfe02b880851e09978bef70f4a986700a28a29ce Mon Sep 17 00:00:00 2001
From: Antoine du Hamel <duhamelantoine1995@gmail.com>
Date: Tue, 27 Apr 2021 16:04:24 +0200
Subject: [PATCH] test,readline: improve tab completion coverage
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PR-URL: https://github.com/nodejs/node/pull/38465
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
---
 test/parallel/test-readline-tab-complete.js | 48 +++++++++++++++++----
 1 file changed, 40 insertions(+), 8 deletions(-)

diff --git a/test/parallel/test-readline-tab-complete.js b/test/parallel/test-readline-tab-complete.js
index e8871863402cb1..e8dcbeebe107ad 100644
--- a/test/parallel/test-readline-tab-complete.js
+++ b/test/parallel/test-readline-tab-complete.js
@@ -31,15 +31,15 @@ common.skipIfDumbTerminal();
     const width = getStringWidth(char) - 1;
 
     class FakeInput extends EventEmitter {
-    columns = ((width + 1) * 10 + (lineBreak ? 0 : 10)) * 3
+      columns = ((width + 1) * 10 + (lineBreak ? 0 : 10)) * 3
 
-    write = common.mustCall((data) => {
-      output += data;
-    }, 6)
+      write = common.mustCall((data) => {
+        output += data;
+      }, 6)
 
-    resume() {}
-    pause() {}
-    end() {}
+      resume() {}
+      pause() {}
+      end() {}
     }
 
     const fi = new FakeInput();
@@ -47,7 +47,7 @@ common.skipIfDumbTerminal();
       input: fi,
       output: fi,
       terminal: true,
-      completer: completer
+      completer: common.mustCallAtLeast(completer),
     });
 
     const last = '\r\nFirst group\r\n\r\n' +
@@ -68,3 +68,35 @@ common.skipIfDumbTerminal();
     rli.close();
   });
 });
+
+{
+  let output = '';
+  class FakeInput extends EventEmitter {
+    columns = 80
+
+    write = common.mustCall((data) => {
+      output += data;
+    }, 1)
+
+    resume() {}
+    pause() {}
+    end() {}
+  }
+
+  const fi = new FakeInput();
+  const rli = new readline.Interface({
+    input: fi,
+    output: fi,
+    terminal: true,
+    completer:
+        common.mustCallAtLeast((_, cb) => cb(new Error('message'))),
+  });
+
+  rli.on('line', common.mustNotCall());
+  fi.emit('data', '\t');
+  queueMicrotask(() => {
+    assert.match(output, /^Tab completion error: Error: message/);
+    output = '';
+  });
+  rli.close();
+}