Improve error message on condition exceptions

Catch exceptions thrown from SpringBootCondition and re-throw with
more context.

See gh-1098

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/condition/SpringBootConditionTests.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2012-2014 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.autoconfigure.condition;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ConditionContext;
+import org.springframework.context.annotation.Conditional;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.type.AnnotatedTypeMetadata;
+
+/**
+ * Tests for {@link SpringBootCondition}.
+ * 
+ * @author Phillip Webb
+ */
+@SuppressWarnings("resource")
+public class SpringBootConditionTests {
+
+	@Rule
+	public ExpectedException thrown = ExpectedException.none();
+
+	@Test
+	public void sensibleClassException() {
+		this.thrown.expect(IllegalStateException.class);
+		this.thrown.expectMessage("Error processing condition on "
+				+ ErrorOnClass.class.getName());
+		new AnnotationConfigApplicationContext(ErrorOnClass.class);
+	}
+
+	@Test
+	public void sensibleMethodException() throws Exception {
+		this.thrown.expect(IllegalStateException.class);
+		this.thrown.expectMessage("Error processing condition on "
+				+ ErrorOnMethod.class.getName() + ".myBean");
+		new AnnotationConfigApplicationContext(ErrorOnMethod.class);
+	}
+
+	@Configuration
+	@Conditional(AlwaysThrowsCondition.class)
+	public static class ErrorOnClass {
+
+	}
+
+	@Configuration
+	public static class ErrorOnMethod {
+
+		@Bean
+		@Conditional(AlwaysThrowsCondition.class)
+		public String myBean() {
+			return "bean";
+		}
+
+	}
+
+	public static class AlwaysThrowsCondition extends SpringBootCondition {
+
+		@Override
+		public ConditionOutcome getMatchOutcome(ConditionContext context,
+				AnnotatedTypeMetadata metadata) {
+			throw new RuntimeException("Oh no!");
+		}
+
+	}
+
+}