add tests

src/lib/input/input-container.spec.ts

@@ -50,7 +50,8 @@ describe('MdInputContainer', function () {
         MdInputContainerMissingMdInputTestController,
         MdInputContainerMultipleHintTestController,
         MdInputContainerMultipleHintMixedTestController,
-        MdInputContainerWithDynamicPlaceholder
+        MdInputContainerWithDynamicPlaceholder,
+        MdInputContainerWithPrefixAndSuffix
       ],
     });
 
@@ -551,6 +552,29 @@ describe('MdInputContainer', function () {
     expect(labelEl.classList).not.toContain('mat-float');
   });
 
+  it('should not have prefix and suffix elements when none are specified', () => {
+    let fixture = TestBed.createComponent(MdInputContainerWithId);
+    fixture.detectChanges();
+
+    let prefixEl = fixture.debugElement.query(By.css('.mat-input-prefix'));
+    let suffixEl = fixture.debugElement.query(By.css('.mat-input-suffix'));
+
+    expect(prefixEl).toBeNull();
+    expect(suffixEl).toBeNull();
+  });
+
+  it('should add prefix and suffix elements when specified', () => {
+    let fixture = TestBed.createComponent(MdInputContainerWithPrefixAndSuffix);
+    fixture.detectChanges();
+
+    let prefixEl = fixture.debugElement.query(By.css('.mat-input-prefix'));
+    let suffixEl = fixture.debugElement.query(By.css('.mat-input-suffix'));
+
+    expect(prefixEl).not.toBeNull();
+    expect(suffixEl).not.toBeNull();
+    expect(prefixEl.nativeElement.innerText.trim()).toEqual('Prefix');
+    expect(suffixEl.nativeElement.innerText.trim()).toEqual('Suffix');
+  });
 });
 
 @Component({
@@ -775,3 +799,14 @@ class MdTextareaWithBindings {
   template: `<md-input-container><input></md-input-container>`
 })
 class MdInputContainerMissingMdInputTestController {}
+
+@Component({
+  template: `
+    <md-input-container>
+      <div mdPrefix>Prefix</div>
+      <input mdInput>
+      <div mdSuffix>Suffix</div>
+    </md-input-container>
+  `
+})
+class MdInputContainerWithPrefixAndSuffix {}