Add evaluation test for template literals

Author: lowr

src/testRunner/tsconfig.json

@@ -99,6 +99,7 @@
         "unittests/evaluation/optionalCall.ts",
         "unittests/evaluation/objectRest.ts",
         "unittests/evaluation/superInStaticInitializer.ts",
+        "unittests/evaluation/templateLiteral.ts",
         "unittests/evaluation/updateExpressionInModule.ts",
         "unittests/services/cancellableLanguageServiceOperations.ts",
         "unittests/services/colorization.ts",

src/testRunner/unittests/evaluation/templateLiteral.ts

@@ -0,0 +1,40 @@
+describe("unittests:: evaluation:: templateLiteral", () => {
+    it("toString() over valueOf()", () => {
+        const result = evaluator.evaluateTypeScript(`
+            class C {
+                toString() {
+                    return "toString";
+                }
+                valueOf() {
+                    return "valueOf";
+                }
+            }
+
+            export const output = \`\${new C}\`;
+        `);
+        assert.strictEqual(result.output, "toString");
+    });
+
+    it("correct evaluation order", () => {
+        const result = evaluator.evaluateTypeScript(`
+            class C {
+                counter: number;
+
+                constructor() {
+                    this.counter = 0;
+                }
+
+                get foo() {
+                    this.counter++;
+                    return {
+                        toString: () => this.counter++,
+                    };
+                }
+            }
+
+            const c = new C;
+            export const output = \`\${c.foo} \${c.foo}\`;
+        `);
+        assert.strictEqual(result.output, "1 3");
+    });
+});