Add profiles directly to the application environment for tests

Prior to this commit, active profiles were being added to the Spring Boot
application environment by setting the `spring.profiles.active` property.
This could result in profiles getting parsed differently than other uses of `@ActiveProfiles`.
Setting the profiles directly in the `Environment` prevents this parsing.

See gh-19556

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/SpringBootContextLoaderTests.java

@@ -22,6 +22,8 @@ import org.junit.Ignore;
 import org.junit.Test;
 
 import org.springframework.context.annotation.Configuration;
+import org.springframework.core.env.Environment;
+import org.springframework.test.context.ActiveProfiles;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.MergedContextConfiguration;
 import org.springframework.test.context.TestContext;
@@ -35,6 +37,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  * Tests for {@link SpringBootContextLoader}
  *
  * @author Stephane Nicoll
+ * @author Scott Frederick
  */
 public class SpringBootContextLoaderTests {
 
@@ -88,13 +91,40 @@ public class SpringBootContextLoaderTests {
 		assertKey(config, "variables", "foo=FOO\n bar=BAR");
 	}
 
+	@Test
+	public void noActiveProfiles() {
+		Environment environment = getApplicationEnvironment(SimpleConfig.class);
+		assertThat(environment.getActiveProfiles()).isEmpty();
+	}
+
+	@Test
+	public void multipleActiveProfiles() {
+		Environment environment = getApplicationEnvironment(MultipleActiveProfiles.class);
+		assertThat(environment.getActiveProfiles()).containsExactly("profile1", "profile2");
+	}
+
+	@Test
+	public void activeProfileWithComma() {
+		Environment environment = getApplicationEnvironment(ActiveProfileWithComma.class);
+		assertThat(environment.getActiveProfiles()).containsExactly("profile1,2");
+	}
+
 	private Map<String, Object> getEnvironmentProperties(Class<?> testClass) {
-		TestContext context = new ExposedTestContextManager(testClass).getExposedTestContext();
+		TestContext context = getTestContext(testClass);
 		MergedContextConfiguration config = (MergedContextConfiguration) ReflectionTestUtils.getField(context,
 				"mergedContextConfiguration");
 		return TestPropertySourceUtils.convertInlinedPropertiesToMap(config.getPropertySourceProperties());
 	}
 
+	private Environment getApplicationEnvironment(Class<?> testClass) {
+		TestContext context = getTestContext(testClass);
+		return context.getApplicationContext().getEnvironment();
+	}
+
+	private TestContext getTestContext(Class<?> testClass) {
+		return new ExposedTestContextManager(testClass).getExposedTestContext();
+	}
+
 	private void assertKey(Map<String, Object> actual, String key, Object value) {
 		assertThat(actual.containsKey(key)).as("Key '" + key + "' not found").isTrue();
 		assertThat(actual.get(key)).isEqualTo(value);
@@ -142,6 +172,20 @@ public class SpringBootContextLoaderTests {
 
 	}
 
+	@SpringBootTest
+	@ActiveProfiles({ "profile1", "profile2" })
+	@ContextConfiguration(classes = Config.class)
+	static class MultipleActiveProfiles {
+
+	}
+
+	@SpringBootTest
+	@ActiveProfiles({ "profile1,2" })
+	@ContextConfiguration(classes = Config.class)
+	static class ActiveProfileWithComma {
+
+	}
+
 	@Configuration
 	static class Config {