I'd create a helper method that sets up the mock for you.  This will make your tests 100% more readable.

```java
public void testNameResolves() {
  bind("test", "1.1.1.1");
  assertEquals("1.1.1.1:2181", _provider.getConnectionString());
}

public void testMultipleRecords() {
  bind("test", "1.1.1.1", "2.2.2.2");
  assertEquals("1.1.1.1:2181,2.2.2.2:2181", _provider.getConnectionString());
}
```

Then the bind method can be a varargs method
```java
void bind(String name, String... ips) {
}
```

For your canonical test, you can call bind a 2nd time
```java
public void testMultipleRecordsCanonical() {
  bind("test", "1.1.1.1", "2.2.2.2");
  assertEquals("1.1.1.1:2181,2.2.2.2:2181", _provider.getConnectionString());

  bind("test", "2.2.2.2", "1.1.1.1");
  assertEquals("1.1.1.1:2181,2.2.2.2:2181", _provider.getConnectionString());
}
```