Test merging lines to str in serial monitor utils

Adds a test for merging one or more lines to a single string. It is
supposed to just concatenate the content of the lines, without doing
anything else. This method is used when copying the serial monitor content to
the clipboard.

Author: 502E532E

arduino-ide-extension/src/test/browser/monitor-utils.test.ts

@@ -2,6 +2,7 @@ import { expect } from 'chai';
 import {
   messagesToLines,
   truncateLines,
+  linesToMergedStr,
 } from '../../browser/serial/monitor/monitor-utils';
 import { Line } from '../../browser/serial/monitor/serial-monitor-send-output';
 import { set, reset } from 'mockdate';
@@ -15,13 +16,15 @@ type TestLine = {
     charCount: number;
     maxCharacters?: number;
   };
+  expectedMerged?: string;
 };
 
 const date = new Date();
 const testLines: TestLine[] = [
   {
     messages: ['Hello'],
     expected: { lines: [{ message: 'Hello', lineLen: 5 }], charCount: 5 },
+    expectedMerged: 'Hello',
   },
   {
     messages: ['Hello', 'Dog!'],
@@ -36,6 +39,7 @@ const testLines: TestLine[] = [
       ],
       charCount: 10,
     },
+    expectedMerged: 'Hello\nDog!'
   },
   {
     messages: ['Dog!'],
@@ -67,6 +71,7 @@ const testLines: TestLine[] = [
         { message: "You're a good boy!", lineLen: 8 },
       ],
     },
+    expectedMerged: "Hello Dog!\n Who's a good boy?\nYou're a good boy!",
   },
   {
     messages: ['boy?\n', "You're a good boy!"],
@@ -116,6 +121,7 @@ const testLines: TestLine[] = [
         { message: 'Yo', lineLen: 2 },
       ],
     },
+    expectedMerged: "Hello Dog!\nWho's a good boy?\nYo",
   },
 ];
 
@@ -165,6 +171,10 @@ describe('Monitor Utils', () => {
           });
           expect(totalCharCount).to.equal(charCount);
         }
+        if (testLine.expectedMerged) {
+          const merged_str = linesToMergedStr(testLine.expected.lines);
+          expect(merged_str).to.equal(testLine.expectedMerged);
+        }
       });
     });
   });