Adding unit tests. Minor code cleanup.

diff --git a/com.google.eclipse.protobuf.ui.test/src/com/google/eclipse/protobuf/ui/util/Strings_firstCharToLowerCase_Test.java b/com.google.eclipse.protobuf.ui.test/src/com/google/eclipse/protobuf/ui/util/Strings_firstCharToLowerCase_Test.java
new file mode 100644
index 0000000..1b4b7a4
--- /dev/null
+++ b/com.google.eclipse.protobuf.ui.test/src/com/google/eclipse/protobuf/ui/util/Strings_firstCharToLowerCase_Test.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2011 Google Inc.
+ *
+ * All rights reserved. This program and the accompanying materials are made available under the terms of the Eclipse
+ * Public License v1.0 which accompanies this distribution, and is available at
+ *
+ * http://www.eclipse.org/legal/epl-v10.html
+ */
+package com.google.eclipse.protobuf.ui.util;
+
+import static org.hamcrest.core.IsEqual.equalTo;
+import static org.hamcrest.core.IsNull.nullValue;
+import static org.junit.Assert.assertThat;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+/**
+ * Tests for <code>{@link Strings#firstCharToLowerCase(String)}</code>
+ *
+ * @author alruiz@google.com (Alex Ruiz)
+ */
+public class Strings_firstCharToLowerCase_Test {
+
+  private static Strings strings;
+  
+  @BeforeClass public static void setUpOnce() {
+    strings = new Strings();
+  }
+  
+  @Test public void should_return_null() {
+    assertThat(strings.firstCharToLowerCase(null), nullValue());
+  }
+
+  @Test public void should_return_empty_String() {
+    assertThat(strings.firstCharToLowerCase(""), equalTo(""));
+  }
+  
+  @Test public void should_return_String_with_first_char_lower_case() {
+    assertThat(strings.firstCharToLowerCase("HElLo"), equalTo("hElLo"));
+  }
+}

diff --git a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/util/Literals.java b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/util/Literals.java
index 2ec9a2f..b4238e9 100644
--- a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/util/Literals.java
+++ b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/util/Literals.java

@@ -9,8 +9,9 @@
 package com.google.eclipse.protobuf.ui.util;
 
 import static java.lang.Math.max;
+import static org.eclipse.xtext.EcoreUtil2.getAllContentsOfType;
 
-import org.eclipse.emf.ecore.EObject;
+import java.util.List;
 
 import com.google.eclipse.protobuf.protobuf.Literal;
 import com.google.inject.Singleton;
@@ -43,10 +44,9 @@
    */
   public int calculateIndexOf(Literal l) {
     int index = -1;
-    EObject container = l.eContainer();
-    for (EObject o : container.eContents()) {
-      if (o == l || !(o instanceof Literal)) continue;
-      Literal c = (Literal) o;
+    List<Literal> allLiterals = getAllContentsOfType(l.eContainer(), Literal.class);
+    for (Literal c : allLiterals) {
+      if (c == l) continue;
       index = max(index, c.getIndex());
     }
     return ++index;

diff --git a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/util/Properties.java b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/util/Properties.java
index 6f0523c..a484024 100644
--- a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/util/Properties.java
+++ b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/util/Properties.java

@@ -9,8 +9,10 @@
 package com.google.eclipse.protobuf.ui.util;
 
 import static java.lang.Math.max;
+import static org.eclipse.xtext.EcoreUtil2.getAllContentsOfType;
 
-import org.eclipse.emf.ecore.EObject;
+import java.util.List;
+
 import org.eclipse.xtext.Keyword;
 
 import com.google.eclipse.protobuf.protobuf.*;
@@ -99,9 +101,9 @@
    */
   public int calculateTagNumberOf(Property p) {
     int index = 0;
-    for (EObject o : p.eContainer().eContents()) {
-      if (o == p || !(o instanceof Property)) continue;
-      Property c = (Property) o;
+    List<Property> allProperties = getAllContentsOfType(p.eContainer(), Property.class);
+    for (Property c : allProperties) {
+      if (c == p) continue;
       index = max(index, c.getIndex());
     }
     return ++index;

diff --git a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/util/Strings.java b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/util/Strings.java
index e20982d..645dee6 100644
--- a/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/util/Strings.java
+++ b/com.google.eclipse.protobuf.ui/src/com/google/eclipse/protobuf/ui/util/Strings.java

@@ -20,6 +20,11 @@
 @Singleton
 public class Strings {
 
+  /**
+   * Returns a {@code String} with the same content as the given one, but with the first character in lower case.
+   * @param s the original {@code String}
+   * @return a {@code String} with the same content as the given one, but with the first character in lower case.
+   */
   public String firstCharToLowerCase(String s) {
     if (s == null) return null;
     if (s.length() == 0) return s;