Simplify StreamConverterTests

Author: sbrannen

spring-core/src/test/java/org/springframework/core/convert/support/StreamConverterTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -30,11 +30,14 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
+import static org.assertj.core.api.InstanceOfAssertFactories.list;
+import static org.assertj.core.api.InstanceOfAssertFactories.stream;
 
 /**
  * Tests for {@link StreamConverter}.
  *
  * @author Stephane Nicoll
+ * @author Sam Brannen
  * @since 4.2
  */
 class StreamConverterTests {
@@ -56,74 +59,53 @@ void setup() {
 	@Test
 	void convertFromStreamToList() throws NoSuchFieldException {
 		this.conversionService.addConverter(Number.class, String.class, new ObjectToStringConverter());
-		Stream<Integer> stream = Arrays.asList(1, 2, 3).stream();
+		Stream<Integer> stream = Stream.of(1, 2, 3);
 		TypeDescriptor listOfStrings = new TypeDescriptor(Types.class.getField("listOfStrings"));
 		Object result = this.conversionService.convert(stream, listOfStrings);
 
-		assertThat(result).as("Converted object must not be null").isNotNull();
-		boolean condition = result instanceof List;
-		assertThat(condition).as("Converted object must be a list").isTrue();
-		@SuppressWarnings("unchecked")
-		List<String> content = (List<String>) result;
-		assertThat(content.get(0)).isEqualTo("1");
-		assertThat(content.get(1)).isEqualTo("2");
-		assertThat(content.get(2)).isEqualTo("3");
-		assertThat(content.size()).as("Wrong number of elements").isEqualTo(3);
+		assertThat(result).asInstanceOf(list(String.class)).containsExactly("1", "2", "3");
 	}
 
 	@Test
 	void convertFromStreamToArray() throws NoSuchFieldException {
 		this.conversionService.addConverterFactory(new NumberToNumberConverterFactory());
-		Stream<Integer> stream = Arrays.asList(1, 2, 3).stream();
+		Stream<Integer> stream = Stream.of(1, 2, 3);
 		TypeDescriptor arrayOfLongs = new TypeDescriptor(Types.class.getField("arrayOfLongs"));
 		Object result = this.conversionService.convert(stream, arrayOfLongs);
 
 		assertThat(result).as("Converted object must not be null").isNotNull();
 		assertThat(result.getClass().isArray()).as("Converted object must be an array").isTrue();
 		Long[] content = (Long[]) result;
-		assertThat(content[0]).isEqualTo(Long.valueOf(1L));
-		assertThat(content[1]).isEqualTo(Long.valueOf(2L));
-		assertThat(content[2]).isEqualTo(Long.valueOf(3L));
-		assertThat(content.length).as("Wrong number of elements").isEqualTo(3);
+		assertThat(content).containsExactly(1L, 2L, 3L);
 	}
 
 	@Test
 	void convertFromStreamToRawList() throws NoSuchFieldException {
-		Stream<Integer> stream = Arrays.asList(1, 2, 3).stream();
+		Stream<Integer> stream = Stream.of(1, 2, 3);
 		TypeDescriptor listOfStrings = new TypeDescriptor(Types.class.getField("rawList"));
 		Object result = this.conversionService.convert(stream, listOfStrings);
 
-		assertThat(result).as("Converted object must not be null").isNotNull();
-		boolean condition = result instanceof List;
-		assertThat(condition).as("Converted object must be a list").isTrue();
-		@SuppressWarnings("unchecked")
-		List<Object> content = (List<Object>) result;
-		assertThat(content.get(0)).isEqualTo(1);
-		assertThat(content.get(1)).isEqualTo(2);
-		assertThat(content.get(2)).isEqualTo(3);
-		assertThat(content.size()).as("Wrong number of elements").isEqualTo(3);
+		assertThat(result).asInstanceOf(list(Object.class)).containsExactly(1, 2, 3);
 	}
 
 	@Test
 	void convertFromStreamToArrayNoConverter() throws NoSuchFieldException {
-		Stream<Integer> stream = Arrays.asList(1, 2, 3).stream();
+		Stream<Integer> stream = Stream.of(1, 2, 3);
 		TypeDescriptor arrayOfLongs = new TypeDescriptor(Types.class.getField("arrayOfLongs"));
-		assertThatExceptionOfType(ConversionFailedException.class).isThrownBy(() ->
-				this.conversionService.convert(stream, arrayOfLongs))
+		assertThatExceptionOfType(ConversionFailedException.class)
+			.isThrownBy(() -> this.conversionService.convert(stream, arrayOfLongs))
 			.withCauseInstanceOf(ConverterNotFoundException.class);
 	}
 
 	@Test
 	@SuppressWarnings("resource")
 	void convertFromListToStream() throws NoSuchFieldException {
 		this.conversionService.addConverterFactory(new StringToNumberConverterFactory());
-		List<String> stream = Arrays.asList("1", "2", "3");
+		List<String> list = Arrays.asList("1", "2", "3");
 		TypeDescriptor streamOfInteger = new TypeDescriptor(Types.class.getField("streamOfIntegers"));
-		Object result = this.conversionService.convert(stream, streamOfInteger);
+		Object result = this.conversionService.convert(list, streamOfInteger);
 
-		assertThat(result).as("Converted object must not be null").isNotNull();
-		boolean condition = result instanceof Stream;
-		assertThat(condition).as("Converted object must be a stream").isTrue();
+		assertThat(result).as("Converted object must be a stream").isInstanceOf(Stream.class);
 		@SuppressWarnings("unchecked")
 		Stream<Integer> content = (Stream<Integer>) result;
 		assertThat(content.mapToInt(x -> x).sum()).isEqualTo(6);
@@ -132,34 +114,25 @@ void convertFromListToStream() throws NoSuchFieldException {
 	@Test
 	@SuppressWarnings("resource")
 	void convertFromArrayToStream() throws NoSuchFieldException {
-		Integer[] stream = new Integer[] {1, 0, 1};
+		Integer[] array = new Integer[] {1, 0, 1};
 		this.conversionService.addConverter(Integer.class, Boolean.class, source -> source == 1);
 		TypeDescriptor streamOfBoolean = new TypeDescriptor(Types.class.getField("streamOfBooleans"));
-		Object result = this.conversionService.convert(stream, streamOfBoolean);
+		Object result = this.conversionService.convert(array, streamOfBoolean);
 
-		assertThat(result).as("Converted object must not be null").isNotNull();
-		boolean condition = result instanceof Stream;
-		assertThat(condition).as("Converted object must be a stream").isTrue();
-		@SuppressWarnings("unchecked")
-		Stream<Boolean> content = (Stream<Boolean>) result;
-		assertThat(content.filter(x -> x).count()).isEqualTo(2);
+		assertThat(result).asInstanceOf(stream(Boolean.class)).filteredOn(x -> x).hasSize(2);
 	}
 
 	@Test
 	@SuppressWarnings("resource")
 	void convertFromListToRawStream() throws NoSuchFieldException {
-		List<String> stream = Arrays.asList("1", "2", "3");
+		List<String> list = Arrays.asList("1", "2", "3");
 		TypeDescriptor streamOfInteger = new TypeDescriptor(Types.class.getField("rawStream"));
-		Object result = this.conversionService.convert(stream, streamOfInteger);
+		Object result = this.conversionService.convert(list, streamOfInteger);
 
-		assertThat(result).as("Converted object must not be null").isNotNull();
-		boolean condition = result instanceof Stream;
-		assertThat(condition).as("Converted object must be a stream").isTrue();
+		assertThat(result).as("Converted object must be a stream").isInstanceOf(Stream.class);
 		@SuppressWarnings("unchecked")
 		Stream<Object> content = (Stream<Object>) result;
-		StringBuilder sb = new StringBuilder();
-		content.forEach(sb::append);
-		assertThat(sb.toString()).isEqualTo("123");
+		assertThat(content).containsExactly("1", "2", "3");
 	}
 
 	@Test