Add test to verify build when input file does not change

Author: sheetalkamat

Diff for: src/testRunner/unittests/tsbuild/outFile.ts

@@ -171,6 +171,22 @@ namespace ts {
             ]
         });
 
+        verifyTscWithEdits({
+            scenario: "outFile",
+            subScenario: "when input file text does not change but its modified time changes",
+            fs: () => outFileFs,
+            commandLineArgs: ["--b", "/src/third", "--verbose"],
+            edits: [
+                {
+                    subScenario: "upstream project changes without changing file text",
+                    modifyFs: fs => {
+                        const time = new Date(fs.time());
+                        fs.utimesSync("/src/first/first_PART1.ts", time, time);
+                    },
+                },
+            ]
+        });
+
         verifyTscCompileLike(testTscCompileLike, {
             scenario: "outFile",
             subScenario: "builds till project specified",

Diff for: src/testRunner/unittests/tsbuild/sample.ts

@@ -138,6 +138,22 @@ namespace ts {
                 ]
             });
 
+            verifyTscWithEdits({
+                scenario: "sample1",
+                subScenario: "when input file text does not change but its modified time changes",
+                fs: () => projFs,
+                commandLineArgs: ["--b", "/src/tests", "--verbose"],
+                edits: [
+                    {
+                        subScenario: "upstream project changes without changing file text",
+                        modifyFs: fs => {
+                            const time = new Date(fs.time());
+                            fs.utimesSync("/src/core/index.ts", time, time);
+                        },
+                    },
+                ]
+            });
+
             verifyTsc({
                 scenario: "sample1",
                 subScenario: "indicates that it would skip builds during a dry build",