More Quality from SonarQube and unit tests

Author: cardil

src/main/java/pl/wavesoftware/eid/exceptions/Eid.java

@@ -191,7 +191,7 @@ public String getUniq() {
         return uniq;
     }
 
-    static void validateFormat(String format, int numSpecifiers) throws IllegalArgumentException {
+    static void validateFormat(String format, int numSpecifiers) {
         if (format == null) {
             throw new IllegalArgumentException("Format can't be null, but just recieved one");
         }
@@ -212,7 +212,7 @@ static void validateFormat(String format, int numSpecifiers) throws IllegalArgum
      * It is used to generate unique ID for each EID object. It's mustn't be secure becouse it just indicate EID object while
      * logging.
      */
-    public static interface UniqIdGenerator {
+    public interface UniqIdGenerator {
 
         /**
          * Generates a uniq string ID
@@ -228,13 +228,13 @@ private static class StdUniqIdGenerator implements UniqIdGenerator {
 
         private final Random random;
 
-        public StdUniqIdGenerator() {
+        private StdUniqIdGenerator() {
             this.random = getUnsecureFastRandom();
         }
 
         @Override
         public String generateUniqId() {
-            long first = abs(random.nextLong());
+            long first = abs(random.nextLong() + 1);
             int second = abs(random.nextInt(Integer.MAX_VALUE));
             int calc = (int) (first + second);
             return Integer.toString(calc, BASE36);

src/test/java/pl/wavesoftware/eid/utils/EidPreconditionsTest.java

@@ -151,6 +151,30 @@ public void testCheckElementIndex() {
         EidPreconditions.checkElementIndex(index, size, eid);
     }
 
+    @Test
+    public void testCheckElementIndex_SizeInvalid() {
+        // given
+        int index = 1;
+        int size = -5;
+        // then
+        thrown.expect(EidIllegalArgumentException.class);
+        thrown.expectMessage(containsString(eid));
+        // when
+        EidPreconditions.checkElementIndex(index, size, eid);
+    }
+
+    @Test
+    public void testCheckElementIndex_Eid_SizeInvalid() {
+        // given
+        int index = 2;
+        int size = -1;
+        // then
+        thrown.expect(EidIllegalArgumentException.class);
+        thrown.expectMessage(containsString(eid));
+        // when
+        EidPreconditions.checkElementIndex(index, size, new Eid(eid));
+    }
+
     @Test
     public void testCheckElementIndex_Positive() {
         // given