1 files changed, 66 insertions, 0 deletions
diff --git a/Userland/Libraries/LibJS/Tests/parser-line-terminators.js b/Userland/Libraries/LibJS/Tests/parser-line-terminators.js
new file mode 100644
index 0000000000..ab88b0eb44
--- /dev/null
+++ b/Userland/Libraries/LibJS/Tests/parser-line-terminators.js
@@ -0,0 +1,66 @@
+/*
+These tests deliberately produce syntax errors to check what line the parser thinks we're on.
+Note that line numbers are higher than you might expect as the parsed code is:
+
+function anonymous(
+) {
+<code>
+}
+
+⚠ PLEASE MAKE SURE TO NOT LET YOUR EDITOR REMOVE THE LS/PS LINE TERMINATORS!
+*/
+
+test("LINE FEED is a line terminator", () => {
+    expect(() => {
+        Function("\n\n@");
+    }).toThrowWithMessage(SyntaxError, "line: 5, column: 1");
+});
+
+test("CARRIAGE RETURN is a line terminator", () => {
+    expect(() => {
+        Function("\r\r@");
+    }).toThrowWithMessage(SyntaxError, "line: 5, column: 1");
+});
+
+test("LINE SEPARATOR is a line terminator", () => {
+    expect(() => {
+        Function("  @");
+    }).toThrowWithMessage(SyntaxError, "line: 5, column: 1");
+});
+
+test("PARAGRAPH SEPARATOR is a line terminator", () => {
+    expect(() => {
+        Function("  @");
+    }).toThrowWithMessage(SyntaxError, "line: 5, column: 1");
+});
+
+test("CR LF is counted as only one line terminator", () => {
+    expect(() => {
+        Function("\r\n\r\n@");
+    }).toThrowWithMessage(SyntaxError, "line: 5, column: 1");
+});
+
+test("LF/CR are not allowed in string literal", () => {
+    expect(() => {
+        Function(`"
+        "`);
+    }).toThrowWithMessage(SyntaxError, "Unexpected token UnterminatedStringLiteral");
+});
+
+test("LS/PS are allowed in string literal", () => {
+    expect(`" "`).toEval();
+    expect(`" "`).toEval();
+});
+
+test("line terminators can be mixed (but please don't)", () => {
+    expect(() => {
+        Function("\r \r\n \n\r@");
+    }).toThrowWithMessage(SyntaxError, "line: 9, column: 1");
+});
+
+test("all line terminators are valid for line continuations", () => {
+    expect(Function('return "a\\\nb"')()).toBe("ab");
+    expect(Function('return "a\\\rb"')()).toBe("ab");
+    expect(Function('return "a\\ b"')()).toBe("ab");
+    expect(Function('return "a\\ b"')()).toBe("ab");
+});