ExternalIdentityRef { @Nullable public String getProviderName() { return providerName; } ExternalIdentityRef(@NotNull String id, @Nullable String providerName); @Nullable String getProviderName(); @NotNull String getId(); @NotNull String getString(); @NotNull static ExternalIdentityRef fromString(@NotNull String str); @Override String toString(); @Override boolean equals(Object o); @Override int hashCode();  }
@Test public void testGetProviderName() { assertNull(refNullProvider.getProviderName()); assertNull(refEmptyProvider.getProviderName()); assertEquals(PROVIDER_NAME, ref.getProviderName()); }