new file mode 100644
--- /dev/null
+++ b/editor/libeditor/tests/test_handle_new_lines.html
@@ -0,0 +1,129 @@
+<!DOCTYPE html>
+<html>
+<head>
+ <title>Test for TextEditRules::HandlingNewLines()</title>
+ <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+ <script type="application/javascript" src="/tests/SimpleTest/EventUtils.js"></script>
+ <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none;">
+
+</div>
+
+<div id="container"></div>
+
+<textarea id="toCopyPlaintext" style="display: none;"></textarea>
+
+<pre id="test">
+
+<script class="testbody" type="application/javascript">
+SimpleTest.waitForExplicitFinish();
+
+async function copyPlaintext(aText) {
+ return new Promise(resolve => {
+ SimpleTest.waitForClipboard(
+ () => { return true; }, // because of mismatch of linebreakers
+ () => {
+ let element = document.getElementById("toCopyPlaintext");
+ element.style.display = "block";
+ element.focus();
+ element.value = aText;
+ synthesizeKey("a", {accelKey: true});
+ synthesizeKey("c", {accelKey: true});
+ },
+ () => {
+ ok(true, `Succeeded to copy "${aText.replace(/\n/g, "\\n").replace(/\r/g, "\\r").replace(/ /g, "\u00A0")}" to clipboard`);
+ let element = document.getElementById("toCopyPlaintext");
+ element.style.display = "none";
+ resolve();
+ },
+ () => {
+ SimpleTest.finish();
+ });
+ });
+}
+
+async function doTests() {
+ // nsIPlaintextEditor::eNewlinesPasteIntact (0):
+ // only remove the leading and trailing newlines.
+ // nsIPlaintextEditor::eNewlinesPasteToFirst (1) or any other value:
+ // remove the first newline and all characters following it.
+ // nsIPlaintextEditor::eNewlinesReplaceWithSpaces (2, Firefox default):
+ // replace newlines with spaces.
+ // nsIPlaintextEditor::eNewlinesStrip (3):
+ // remove newlines from the string.
+ // nsIPlaintextEditor::eNewlinesReplaceWithCommas (4, Thunderbird default):
+ // replace newlines with commas.
+ // nsIPlaintextEditor::eNewlinesStripSurroundingWhitespace (5):
+ // collapse newlines and surrounding whitespace characters and
+ // remove them from the string.
+
+ // value: setting or pasting text.
+ // expected: array of final values for each above pref value.
+ // setValue: expected result when HTMLInputElement.value is set to the value.
+ // pasteValue: expected result when pasting the value from clipboard.
+ //
+ // Note that HTMLInputElement strips both \r and \n. Therefore, each expected
+ // result is different from pasting the value.
+ const kTests = [
+ { value: "\nabc\ndef\n",
+ expected: [{ setValue: "abcdef", pasteValue: "abc\ndef" },
+ { setValue: "abcdef", pasteValue: "abc" },
+ { setValue: "abcdef", pasteValue: " abc def" },
+ { setValue: "abcdef", pasteValue: "abcdef" },
+ { setValue: "abcdef", pasteValue: "abc,def" },
+ { setValue: "abcdef", pasteValue: "abcdef" }],
+ },
+ { value: "\n abc \n def \n",
+ expected: [{ setValue: " abc def ", pasteValue: " abc \n def " },
+ { setValue: " abc def ", pasteValue: " abc " },
+ { setValue: " abc def ", pasteValue: " abc def " },
+ { setValue: " abc def ", pasteValue: " abc def " },
+ { setValue: " abc def ", pasteValue: " abc , def " },
+ { setValue: " abc def ", pasteValue: "abcdef" }],
+ },
+ { value: " abc \n def ",
+ expected: [{ setValue: " abc def ", pasteValue: " abc \n def " },
+ { setValue: " abc def ", pasteValue: " abc " },
+ { setValue: " abc def ", pasteValue: " abc def " },
+ { setValue: " abc def ", pasteValue: " abc def " },
+ { setValue: " abc def ", pasteValue: " abc , def " },
+ { setValue: " abc def ", pasteValue: " abcdef " }],
+ },
+ ];
+
+ let container = document.getElementById("container");
+ for (let i = 0; i <= 5; i++) {
+ await SpecialPowers.pushPrefEnv({"set": [["editor.singleLine.pasteNewlines", i]]});
+ container.innerHTML = `<input id="input${i}" type="text">`;
+ let input = document.getElementById(`input${i}`);
+ input.focus();
+ let editor = SpecialPowers.wrap(input).editor;
+ for (const kLineBreaker of ["\n", "\r", "\r\n"]) {
+ for (let kTest of kTests) {
+ let value = kTest.value.replace(/\n/g, kLineBreaker);
+ input.value = value;
+ is(editor.rootElement.firstChild.wholeText, kTest.expected[i].setValue,
+ `Setting value to "${value.replace(/\n/g, "\\n").replace(/\r/g, "\\r").replace(/ /g, "\u00A0")}" when pref is ${i}`);
+ input.value = "";
+
+ await copyPlaintext(value);
+ input.focus();
+ synthesizeKey("v", {accelKey: true});
+ is(editor.rootElement.firstChild.wholeText, kTest.expected[i].pasteValue,
+ `Pasting "${value.replace(/\n/g, "\\n").replace(/\r/g, "\\r").replace(/ /g, "\u00A0")}" when pref is ${i}`);
+ input.value = "";
+ }
+ }
+ }
+
+ SimpleTest.finish();
+}
+
+SimpleTest.waitForFocus(doTests);
+</script>
+</pre>
+</body>
+</html>