Add failing test for watching file outside of tsconfig root files

Author: andrewbranch

internal/project/session_test.go

@@ -6,6 +6,8 @@ import (
 	"testing"
 
 	"github.com/microsoft/typescript-go/internal/bundled"
+	"github.com/microsoft/typescript-go/internal/core"
+	"github.com/microsoft/typescript-go/internal/glob"
 	"github.com/microsoft/typescript-go/internal/lsp/lsproto"
 	"github.com/microsoft/typescript-go/internal/testutil/projecttestutil"
 	"github.com/microsoft/typescript-go/internal/tspath"
@@ -548,6 +550,55 @@ func TestSession(t *testing.T) {
 			assert.Check(t, lsAfter.GetProgram() != programBefore)
 		})
 
+		t.Run("change program file not in tsconfig root files", func(t *testing.T) {
+			t.Parallel()
+			files := map[string]any{
+				"/home/projects/TS/p1/tsconfig.json": `{
+					"compilerOptions": {
+						"noLib": true,
+						"module": "nodenext",
+						"strict": true
+					},
+					"files": ["src/index.ts"]
+				}`,
+				"/home/projects/TS/p1/src/index.ts": `import { x } from "../../x";`,
+				"/home/projects/TS/x.ts":            `export const x = 1;`,
+			}
+
+			session, utils := projecttestutil.Setup(files)
+			session.DidOpenFile(context.Background(), "file:///home/projects/TS/p1/src/index.ts", 1, files["/home/projects/TS/p1/src/index.ts"].(string), lsproto.LanguageKindTypeScript)
+			lsBefore, err := session.GetLanguageService(context.Background(), "file:///home/projects/TS/p1/src/index.ts")
+			assert.NilError(t, err)
+			programBefore := lsBefore.GetProgram()
+			session.WaitForBackgroundTasks()
+
+			var xWatched bool
+		outer:
+			for _, call := range utils.Client().WatchFilesCalls() {
+				for _, watcher := range call.Watchers {
+					if core.Must(glob.Parse(*watcher.GlobPattern.Pattern)).Match("/home/projects/TS/x.ts") {
+						xWatched = true
+						break outer
+					}
+				}
+			}
+			assert.Check(t, xWatched)
+
+			err = utils.FS().WriteFile("/home/projects/TS/x.ts", `export const x = 2;`, false)
+			assert.NilError(t, err)
+
+			session.DidChangeWatchedFiles(context.Background(), []*lsproto.FileEvent{
+				{
+					Type: lsproto.FileChangeTypeChanged,
+					Uri:  "file:///home/projects/TS/x.ts",
+				},
+			})
+
+			lsAfter, err := session.GetLanguageService(context.Background(), "file:///home/projects/TS/p1/src/index.ts")
+			assert.NilError(t, err)
+			assert.Check(t, lsAfter.GetProgram() != programBefore)
+		})
+
 		t.Run("change config file", func(t *testing.T) {
 			t.Parallel()
 			files := map[string]any{