Replace hamcrest with assertj

[fil512]

This merge request replaces practically all usages of hamcrest with assertj.

One thing I wanted to include in this MR but was unable to was to run checkstyle on all our tests and add a checkstyle to enforce no hamcrest imports.

I also tried to remove the hamcrest jar entirely, but sadly it is currently required by awaitility. I opened a ticket a ticket with awaitility asking them if they had considered switching from hamcrest to assertj.

Some tricky cases noted here:
(1)

		assertThat(composition.getText().getDivAsString(), stringContainsInOrder(
			"Vax 2015", "Vax 2010", "Vax 2005"
		));

becomes

		assertThat(composition.getText().getDivAsString()).containsSubsequence(
                        "Vax 2015", "Vax 2010", "Vax 2005"
                 );

(2)

                 assertThat(x, either(equalTo("a"), or(equalTo("b")));

becomes

                assertThat(x).isIn("a", "b");

(3)

       		assertThat(messageString, not(stringContainsInOrder(
			"extension",
			"meta"
		)));

becomes

       		assertThat(messageString).doesNotContainPattern("(?s)extension.*meta");

(4)

assertThat(myCaptureQueriesListener.getSelectQueries().get(0).getSql(true, false),
  either(containsString("rt1_0.RES_TYPE='Patient' and rt1_0.FHIR_ID='B' and rt1_0.PARTITION_ID is null or rt1_0.RES_TYPE='Patient' and rt1_0.FHIR_ID='A' and rt1_0.PARTITION_ID is null"))
  .or(containsString("rt1_0.RES_TYPE='Patient' and rt1_0.FHIR_ID='A' and rt1_0.PARTITION_ID is null or rt1_0.RES_TYPE='Patient' and rt1_0.FHIR_ID='B' and rt1_0.PARTITION_ID is null")));

becomes

assertThat(sql).satisfiesAnyOf(
  s -> assertThat(s).contains("rt1_0.RES_TYPE='Patient' and rt1_0.FHIR_ID='B' and rt1_0.PARTITION_ID is null or rt1_0.RES_TYPE='Patient' and rt1_0.FHIR_ID='A' and rt1_0.PARTITION_ID is null"),
  s -> assertThat(s).contains("rt1_0.RES_TYPE='Patient' and rt1_0.FHIR_ID='A' and rt1_0.PARTITION_ID is null or rt1_0.RES_TYPE='Patient' and rt1_0.FHIR_ID='B' and rt1_0.PARTITION_ID is null")
);

[dotasek]

@fil512 I did a review of ~50 randomly chosen test files, including all contents of hapi-fhir-test-util.

Some of them, particularly those that suggest switching to assertThatThrownBy(), isEqualTo() or contains(), are probably nitpicky, and you can feel free to mark them as resolved.

There are a few regarding test asserts that are always true, and some that appear to test nothing except assertj itself that I'm more interested in.

This looks like it was a long haul, @fil512 @tadgh, your patience with this is laudable!

[dotasek]

I resolved the outstanding assertThatThrownBy() requested changes after your comments on the first few. If you find any left, they're clearly fine to resolve.