Add test for @line expressions

Author: CodaFi

Tests/FileCheckTests/LineCountSpec.swift

@@ -5,21 +5,20 @@ import Foundation
 
 class LineCountSpec : XCTestCase {
   func testLineCount() {
-    let txt = [
-      "9",
-      "10 aaa",
-      "11 bbb",
-      "12 ccc",
-      "13 CHECK-LINECOUNT: [[@LINE-3]] {{a}}aa",
-      "14 CHECK-LINECOUNT: [[@LINE-3]] {{b}}bb",
-      "15 CHECK-LINECOUNT: [[@LINE-3]] {{c}}cc",
-      "16 foobar",
-      "17 CHECK-LINECOUNT: [[@LINE-1]] {{foo}}bar",
-      "18",
-      "19 arst CHECK-LINECOUNT: [[@LINE]] {{a}}rst",
-      "20",
-      "21 BAD-CHECK-LINECOUNT: [[@LINE:cant-have-regex]]",
-    ].joined(separator: "\n")
+    let txt = ((1...8).map({ "\($0)" }) + [
+        "9 aaa"
+      , "10 bbb"
+      , "11 ccc", "", "", ""
+      // 12 CHECK-LINECOUNT: [[@LINE-3]] {{a}}aa
+      // 13 CHECK-LINECOUNT: [[@LINE-3]] {{b}}bb
+      // 14 CHECK-LINECOUNT: [[@LINE-3]] {{c}}cc
+      , "15 foobar", ""
+      // 16 CHECK-LINECOUNT: [[@LINE-1]] {{foo}}bar
+      , "17", "18 arst"
+      // CHECK-LINECOUNT: [[@LINE]] {{a}}rst
+      , "19"
+      // 20 BAD-CHECK-LINECOUNT: [[@LINE:cant-have-regex]]
+    ]).joined(separator: "\n")
 
     XCTAssert(fileCheckOutput(of: .stdout, withPrefixes: ["CHECK-LINECOUNT"]) {
       print(txt)