BindingsEnvironmentPostProcessor

The previous implementation was *so* complex!  I realize that you grabbed it
from the previous implementation, but you ran into one of our biggest
failings, too much complexity, too early.  Among other things the looping
priority was inverted (looping on the wrong thing).  This simplifies the whole
into a handful of lines, and once again notice the judicious use of
constructors to make it testable.

Signed-off-by: Ben Hale <bhale@vmware.com>

cnb-bindings-boot/src/main/java/org/springframework/cloud/cnb/boot/CassandraCnbBindingProcessor.java

@@ -15,7 +15,7 @@
  */
 package org.springframework.cloud.cnb.boot;
 
-import org.springframework.cloud.cnb.core.Binding;
+import org.springframework.cloud.cnb.Binding;
 
 import java.util.Map;
 

cnb-bindings-boot/src/main/java/org/springframework/cloud/cnb/boot/CnbBindingProcessor.java

@@ -17,7 +17,7 @@ package org.springframework.cloud.cnb.boot;
 
 import java.util.Map;
 
-import org.springframework.cloud.cnb.core.Binding;
+import org.springframework.cloud.cnb.Binding;
 
 public interface CnbBindingProcessor {
 

cnb-bindings-boot/src/main/java/org/springframework/cloud/cnb/boot/CnbBindingsPostProcessor.java

@@ -25,8 +25,8 @@ import org.springframework.boot.context.config.ConfigFileApplicationListener;
 import org.springframework.boot.context.event.ApplicationPreparedEvent;
 import org.springframework.boot.env.EnvironmentPostProcessor;
 import org.springframework.cloud.cnb.core.CNBBindingsSingleton;
-import org.springframework.cloud.cnb.core.Binding;
-import org.springframework.cloud.cnb.core.Bindings;
+import org.springframework.cloud.cnb.Binding;
+import org.springframework.cloud.cnb.Bindings;
 import org.springframework.context.ApplicationEvent;
 import org.springframework.context.ApplicationListener;
 import org.springframework.core.Ordered;

cnb-bindings-boot/src/main/java/org/springframework/cloud/cnb/boot/DataSourceCnbBindingProcessor.java

@@ -17,7 +17,7 @@ package org.springframework.cloud.cnb.boot;
 
 import java.util.Map;
 
-import org.springframework.cloud.cnb.core.Binding;
+import org.springframework.cloud.cnb.Binding;
 import org.springframework.cloud.cnb.jdbc.JdbcBinding;
 
 

cnb-bindings-boot/src/main/java/org/springframework/cloud/cnb/boot/MongoCnbBindingProcessor.java

@@ -17,7 +17,7 @@ package org.springframework.cloud.cnb.boot;
 
 import java.util.Map;
 
-import org.springframework.cloud.cnb.core.Binding;
+import org.springframework.cloud.cnb.Binding;
 
 public class MongoCnbBindingProcessor implements CnbBindingProcessor {
     private static final String MONGO_KIND = "mongodb";

cnb-bindings-boot/src/main/java/org/springframework/cloud/cnb/boot/RedisCnbBindingProcessor.java

@@ -17,7 +17,7 @@ package org.springframework.cloud.cnb.boot;
 
 import java.util.Map;
 
-import org.springframework.cloud.cnb.core.Binding;
+import org.springframework.cloud.cnb.Binding;
 
 
 public class RedisCnbBindingProcessor implements CnbBindingProcessor {

cnb-bindings-boot/src/test/java/org/springframework/cloud/cnb/boot/CassandraCnbBindingProcessorTests.java

@@ -20,7 +20,7 @@ import java.util.Map;
 
 import org.junit.Test;
 
-import org.springframework.cloud.cnb.core.Binding;
+import org.springframework.cloud.cnb.Binding;
 
 
 import static org.assertj.core.api.Assertions.assertThat;

cnb-bindings-boot/src/test/java/org/springframework/cloud/cnb/boot/DataSourceCnbBindingProcessorTests.java

@@ -21,7 +21,7 @@ import java.util.Map;
 
 import org.junit.Test;
 
-import org.springframework.cloud.cnb.core.Binding;
+import org.springframework.cloud.cnb.Binding;
 
 
 import static org.assertj.core.api.Assertions.assertThat;

cnb-bindings-boot/src/test/java/org/springframework/cloud/cnb/boot/MongoCnbBindingProcessorTests.java

@@ -21,7 +21,7 @@ import java.util.Map;
 
 import org.junit.Test;
 
-import org.springframework.cloud.cnb.core.Binding;
+import org.springframework.cloud.cnb.Binding;
 
 
 import static org.assertj.core.api.Assertions.assertThat;

cnb-bindings-boot/src/test/java/org/springframework/cloud/cnb/boot/RedisCnbBindingProcessorTests.java

@@ -21,7 +21,7 @@ import java.util.Map;
 
 import org.junit.Test;
 
-import org.springframework.cloud.cnb.core.Binding;
+import org.springframework.cloud.cnb.Binding;
 
 
 import static org.assertj.core.api.Assertions.assertThat;

cnb-bindings-boot/src/test/java/org/springframework/cloud/cnb/boot/test/EnvMock.java

@@ -21,7 +21,7 @@ import java.util.Map;
 
 import mockit.MockUp;
 
-import org.springframework.cloud.cnb.core.Bindings;
+import org.springframework.cloud.cnb.Bindings;
 
 
 /**

cnb-bindings-boot/src/test/java/org/springframework/cloud/cnb/boot/test/TestJdbcKind.java

@@ -15,7 +15,7 @@
  */
 package org.springframework.cloud.cnb.boot.test;
 
-import org.springframework.cloud.cnb.core.Binding;
+import org.springframework.cloud.cnb.Binding;
 import org.springframework.cloud.cnb.jdbc.JdbcKind;
 
 public class TestJdbcKind implements JdbcKind {

cnb-bindings-jdbc/src/main/java/org/springframework/cloud/cnb/jdbc/DB2JdbcKind.java

@@ -15,7 +15,7 @@
  */
 package org.springframework.cloud.cnb.jdbc;
 
-import org.springframework.cloud.cnb.core.Binding;
+import org.springframework.cloud.cnb.Binding;
 
 public class DB2JdbcKind implements JdbcKind{
 

cnb-bindings-jdbc/src/main/java/org/springframework/cloud/cnb/jdbc/JdbcBinding.java

@@ -17,7 +17,7 @@ package org.springframework.cloud.cnb.jdbc;
 
 import java.util.ServiceLoader;
 
-import org.springframework.cloud.cnb.core.Binding;
+import org.springframework.cloud.cnb.Binding;
 import org.springframework.cloud.cnb.core.IllegalBindingException;
 
 

cnb-bindings-jdbc/src/main/java/org/springframework/cloud/cnb/jdbc/JdbcKind.java

@@ -15,7 +15,7 @@
  */
 package org.springframework.cloud.cnb.jdbc;
 
-import org.springframework.cloud.cnb.core.Binding;
+import org.springframework.cloud.cnb.Binding;
 
 public interface JdbcKind {
     boolean forBinding(Binding binding);

cnb-bindings-jdbc/src/main/java/org/springframework/cloud/cnb/jdbc/MysqlJdbcKind.java

@@ -15,7 +15,7 @@
  */
 package org.springframework.cloud.cnb.jdbc;
 
-import org.springframework.cloud.cnb.core.Binding;
+import org.springframework.cloud.cnb.Binding;
 
 public class MysqlJdbcKind implements JdbcKind{
 

cnb-bindings-jdbc/src/main/java/org/springframework/cloud/cnb/jdbc/OracleJdbcKind.java

@@ -15,7 +15,7 @@
  */
 package org.springframework.cloud.cnb.jdbc;
 
-import org.springframework.cloud.cnb.core.Binding;
+import org.springframework.cloud.cnb.Binding;
 
 public class OracleJdbcKind implements JdbcKind{
 

cnb-bindings-jdbc/src/main/java/org/springframework/cloud/cnb/jdbc/PostgresJdbcKind.java

@@ -18,7 +18,7 @@ package org.springframework.cloud.cnb.jdbc;
 import java.util.Arrays;
 import java.util.List;
 
-import org.springframework.cloud.cnb.core.Binding;
+import org.springframework.cloud.cnb.Binding;
 
 
 public class PostgresJdbcKind implements JdbcKind{

cnb-bindings-jdbc/src/main/java/org/springframework/cloud/cnb/jdbc/SqlServerJdbcKind.java

@@ -15,7 +15,7 @@
  */
 package org.springframework.cloud.cnb.jdbc;
 
-import org.springframework.cloud.cnb.core.Binding;
+import org.springframework.cloud.cnb.Binding;
 
 public class SqlServerJdbcKind implements JdbcKind{
 

cnb-bindings-jdbc/src/test/java/org/springframework/cloud/cnb/jdbc/JdbcBindingTest.java

@@ -20,7 +20,7 @@ import java.util.Map;
 
 import org.junit.Test;
 
-import org.springframework.cloud.cnb.core.Binding;
+import org.springframework.cloud.cnb.Binding;
 
 import static org.assertj.core.api.Assertions.assertThat;
 

cnb-bindings/pom.xml

@@ -1,4 +1,20 @@
 <?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Copyright 2020 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.
+  -->
+
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 
@@ -20,6 +36,11 @@
             <artifactId>annotations</artifactId>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter</artifactId>
+            <scope>provided</scope>
+        </dependency>
 
         <dependency>
             <groupId>org.springframework.boot</groupId>

cnb-bindings/src/main/java/org/springframework/cloud/bindings/Binding.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2019 the original author or authors.
+ * Copyright 2020 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.
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.springframework.cloud.cnb.core;
+package org.springframework.cloud.bindings;
 
 import org.jetbrains.annotations.NotNull;
 

cnb-bindings/src/main/java/org/springframework/cloud/bindings/Bindings.java

@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.springframework.cloud.cnb.core;
+package org.springframework.cloud.bindings;
 
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -23,9 +23,9 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
-import java.util.Map;
 import java.util.stream.Collectors;
 
 
@@ -58,35 +58,34 @@ public final class Bindings {
      *
      * @param path the path to populate the {@code Bindings} from.
      */
-    public Bindings(@NotNull String path) {
+    public Bindings(String path) {
+        if (path == null) {
+            this.bindings = Collections.emptyList();
+            return;
+        }
+
         Path p = Paths.get(path);
 
         if (!Files.exists(p)) {
             this.bindings = Collections.emptyList();
-        } else if (!Files.isDirectory(p)) {
+            return;
+        }
+
+        if (!Files.isDirectory(p)) {
             throw new IllegalArgumentException(String.format("%s is not a directory", p));
-        } else {
-            try {
-                this.bindings = Files.list(p)
-                        .map(Binding::new)
-                        .collect(Collectors.toList());
-            } catch (IOException e) {
-                throw new IllegalStateException(String.format("unable to list children of '%s'", path), e);
-            }
+        }
+
+        try {
+            this.bindings = Files.list(p)
+                    .map(Binding::new)
+                    .collect(Collectors.toList());
+        } catch (IOException e) {
+            throw new IllegalStateException(String.format("unable to list children of '%s'", path), e);
         }
     }
 
-    /**
-     * Indicates whether the {@code $CNB_BINDINGS} is and zero or more bindings will be available.
-     *
-     * @return {@code true} if {@code $CNB_BINDINGS} is set, {@code false} otherwise.
-     */
-    public static boolean hasBindings() {
-        return hasBindings(System.getenv());
-    }
-
-    static boolean hasBindings(@NotNull Map<String, String> environment) {
-        return environment.containsKey(CNB_BINDINGS);
+    Bindings(@NotNull Binding... bindings) {
+        this.bindings = Arrays.asList(bindings);
     }
 
     /**
@@ -113,13 +112,13 @@ public final class Bindings {
     }
 
     /**
-     * Returns zero or more {@link Binding}s with a given kind.  Equivalent to {@link #getBindings(String, String)}.
+     * Returns zero or more {@link Binding}s with a given kind.  Equivalent to {@link #filterBindings(String, String)}.
      *
      * @param kind the kind of the {@code Binding} to find.
      * @return the collection of {@code Binding}s with a given kind.
      */
-    public @NotNull List<Binding> getBindings(@Nullable String kind) {
-        return getBindings(kind, null);
+    public @NotNull List<Binding> filterBindings(@Nullable String kind) {
+        return filterBindings(kind, null);
     }
 
     /**
@@ -130,7 +129,7 @@ public final class Bindings {
      * @param provider the provider of {@code Binding} to find
      * @return the collection of {@code Binding}s with a given kind and provider.
      */
-    public @NotNull List<Binding> getBindings(@Nullable String kind, @Nullable String provider) {
+    public @NotNull List<Binding> filterBindings(@Nullable String kind, @Nullable String provider) {
         List<Binding> filtered = new ArrayList<>();
 
         for (Binding binding : bindings) {

cnb-bindings/src/main/java/org/springframework/cloud/bindings/BindingsEnvironmentPostProcessor.java

@@ -0,0 +1,112 @@
+/*
+ * Copyright 2020 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.cloud.bindings;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.jetbrains.annotations.NotNull;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.context.config.ConfigFileApplicationListener;
+import org.springframework.boot.env.EnvironmentPostProcessor;
+import org.springframework.core.Ordered;
+import org.springframework.core.annotation.AnnotationAwareOrderComparator;
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.env.MapPropertySource;
+import org.springframework.core.env.MutablePropertySources;
+import org.springframework.core.env.PropertySource;
+import org.springframework.core.io.support.SpringFactoriesLoader;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import static org.springframework.core.env.CommandLinePropertySource.COMMAND_LINE_PROPERTY_SOURCE_NAME;
+
+/**
+ * An implementation of {@link EnvironmentPostProcessor} that delegates properties generation from {@link Bindings}.
+ * This implementation generates a single instance of {@code Bindings} and then calls all implementations of
+ * {@link BindingsPropertiesProcessor} registered with {@link SpringFactoriesLoader} allowing them to generate any
+ * properties from the contents of the {@code Bindings}.
+ */
+public final class BindingsEnvironmentPostProcessor implements EnvironmentPostProcessor, Ordered {
+
+    /**
+     * The name of the {@link PropertySource} created by the {@code BindingsEnvironmentPostProcessor}: {@value}.
+     */
+    public static final String BINDINGS_PROPERTY_SOURCE_NAME = "cnbBindings";
+
+    private final Log log = LogFactory.getLog(getClass());
+
+    private final Bindings bindings;
+
+    private final List<BindingsPropertiesProcessor> processors;
+
+    /**
+     * Creates a new instance of {@code BindingsEnvironmentPostProcessor} using the {@link Bindings} available in the
+     * environment and the {@link BindingsPropertiesProcessor}s registered with {@link SpringFactoriesLoader}.
+     */
+    public BindingsEnvironmentPostProcessor() {
+        this.bindings = new Bindings();
+        this.processors = SpringFactoriesLoader.
+                loadFactories(BindingsPropertiesProcessor.class, getClass().getClassLoader());
+        AnnotationAwareOrderComparator.sort(this.processors);
+    }
+
+    BindingsEnvironmentPostProcessor(@NotNull Bindings bindings,
+                                     @NotNull BindingsPropertiesProcessor... processors) {
+
+        this.bindings = bindings;
+        this.processors = Arrays.asList(processors);
+    }
+
+    @Override
+    public void postProcessEnvironment(@NotNull ConfigurableEnvironment environment,
+                                       @NotNull SpringApplication application) {
+
+        if (bindings.getBindings().isEmpty()) {
+            log.debug("No CNB Bindings found. Skipping Environment post-processing.");
+            return;
+        }
+
+        Map<String, Object> properties = new HashMap<>();
+        for (BindingsPropertiesProcessor processor : processors) {
+            processor.process(bindings, properties);
+        }
+        if (properties.isEmpty()) {
+            log.debug("No properties set from CNB Bindings. Skipping PropertySource creation.");
+            return;
+        }
+
+        log.info("Creating PropertySource from CNB Bindings");
+        MutablePropertySources propertySources = environment.getPropertySources();
+        MapPropertySource propertySource = new MapPropertySource(BINDINGS_PROPERTY_SOURCE_NAME, properties);
+
+        if (propertySources.contains(COMMAND_LINE_PROPERTY_SOURCE_NAME)) {
+            propertySources.addAfter(COMMAND_LINE_PROPERTY_SOURCE_NAME, propertySource);
+        } else {
+            propertySources.addFirst(propertySource);
+        }
+    }
+
+    @Override
+    public int getOrder() {
+        // Before ConfigFileApplicationListener so values there can use values from {@link Bindings}.
+        return ConfigFileApplicationListener.DEFAULT_ORDER - 1;
+    }
+
+}

cnb-bindings/src/main/java/org/springframework/cloud/bindings/BindingsPropertiesProcessor.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2020 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.cloud.bindings;
+
+import org.springframework.lang.NonNull;
+
+import java.util.Map;
+
+/**
+ * An interface for types that transform the contents of a {@link Bindings} into properties for injection into a
+ * {@link org.springframework.core.env.PropertySource}.
+ */
+@FunctionalInterface
+public interface BindingsPropertiesProcessor {
+
+    /**
+     * Transform the currently accumulated {@link Bindings}-related properties.
+     *
+     * @param bindings   the {@code Bindings} exposed to the application.
+     * @param properties the currently accumulated properties.
+     */
+    void process(@NonNull Bindings bindings, @NonNull Map<String, Object> properties);
+
+}

cnb-bindings/src/main/resources/META-INF/spring.factories

@@ -0,0 +1,2 @@
+org.springframework.boot.env.EnvironmentPostProcessor=\
+  org.springframework.cloud.bindings.BindingsEnvironmentPostProcessor

cnb-bindings/src/test/java/org/springframework/cloud/bindings/BindingTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2019 the original author or authors.
+ * Copyright 2020 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.
@@ -13,18 +13,21 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.springframework.cloud.cnb.core;
+package org.springframework.cloud.bindings;
 
 
+import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 
 import java.nio.file.Paths;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
+@DisplayName("Binding")
 final class BindingTest {
 
     @Test
+    @DisplayName("populates content from filesystem")
     void test() {
         Binding binding = new Binding(Paths.get("src/test/resources/test-name-1"));
 

cnb-bindings/src/test/java/org/springframework/cloud/bindings/BindingsEnvironmentPostProcessorTest.java

@@ -0,0 +1,116 @@
+/*
+ * Copyright 2020 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.cloud.bindings;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.context.config.ConfigFileApplicationListener;
+import org.springframework.core.env.PropertySource;
+import org.springframework.core.env.SimpleCommandLinePropertySource;
+import org.springframework.mock.env.MockEnvironment;
+
+import java.nio.file.Paths;
+import java.util.Collections;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.cloud.bindings.BindingsEnvironmentPostProcessor.BINDINGS_PROPERTY_SOURCE_NAME;
+
+@DisplayName("Bindings EnvironmentPostProcessor")
+final class BindingsEnvironmentPostProcessorTest {
+
+    private final SpringApplication application = new SpringApplication();
+
+    private final MockEnvironment environment = new MockEnvironment();
+
+    @Test
+    @DisplayName("does not create PropertySource if no bindings")
+    void noBindings() {
+        new BindingsEnvironmentPostProcessor(new Bindings()).postProcessEnvironment(environment, application);
+
+        assertThat(environment.getPropertySources()).hasSize(1);
+    }
+
+    @Test
+    @DisplayName("does not create PropertySource if no properties")
+    void noProperties() {
+        new BindingsEnvironmentPostProcessor(
+                new Bindings(
+                        new Binding("test-name", Paths.get("test-path"),
+                                Collections.emptyMap(), Collections.emptyMap())
+                )
+        ).postProcessEnvironment(environment, application);
+
+        assertThat(environment.getPropertySources()).hasSize(1);
+    }
+
+    @Test
+    @DisplayName("creates PropertySource with properties")
+    void containsProperties() {
+        new BindingsEnvironmentPostProcessor(
+                new Bindings(
+                        new Binding("test-name", Paths.get("test-path"),
+                                Collections.emptyMap(), Collections.emptyMap())
+                ),
+                (environment, properties) -> properties.put("test-key", "test-value")
+        ).postProcessEnvironment(environment, application);
+
+        assertThat(environment.getPropertySources()).hasSize(2);
+        assertThat(environment.getProperty("test-key")).isEqualTo("test-value");
+    }
+
+    @Test
+    @DisplayName("adds PropertySource after CommandLinePropertySource")
+    void withCommandLinePropertySource() {
+        environment.getPropertySources().addFirst(new SimpleCommandLinePropertySource());
+
+        new BindingsEnvironmentPostProcessor(
+                new Bindings(
+                        new Binding("test-name", Paths.get("test-path"),
+                                Collections.emptyMap(), Collections.emptyMap())
+                ),
+                (environment, properties) -> properties.put("test-key", "test-value")
+        ).postProcessEnvironment(environment, application);
+
+        PropertySource<?> propertySource = environment.getPropertySources().get(BINDINGS_PROPERTY_SOURCE_NAME);
+        assertThat(propertySource).isNotNull();
+        assertThat(environment.getPropertySources().precedenceOf(propertySource)).isEqualTo(1);
+    }
+
+    @Test
+    @DisplayName("adds PropertySource first")
+    void withoutCommandLinePropertySource() {
+        new BindingsEnvironmentPostProcessor(
+                new Bindings(
+                        new Binding("test-name", Paths.get("test-path"),
+                                Collections.emptyMap(), Collections.emptyMap())
+                ),
+                (environment, properties) -> properties.put("test-key", "test-value")
+        ).postProcessEnvironment(environment, application);
+
+        PropertySource<?> propertySource = environment.getPropertySources().get(BINDINGS_PROPERTY_SOURCE_NAME);
+        assertThat(propertySource).isNotNull();
+        assertThat(environment.getPropertySources().precedenceOf(propertySource)).isEqualTo(0);
+    }
+
+    @Test
+    @DisplayName("has order before ConfigFileApplicationListener")
+    void order() {
+        assertThat(new BindingsEnvironmentPostProcessor(new Bindings()).getOrder())
+                .isLessThan(ConfigFileApplicationListener.DEFAULT_ORDER);
+    }
+}

cnb-bindings/src/test/java/org/springframework/cloud/bindings/BindingsTests.java

@@ -0,0 +1,113 @@
+/*
+ * Copyright 2020 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.cloud.bindings;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Paths;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+
+@DisplayName("Bindings")
+final class BindingsTests {
+
+    @Nested
+    @DisplayName("Constructor")
+    final class Constructor {
+
+        @Test
+        @DisplayName("empty if path is null")
+        void nullPath() {
+            Bindings b = new Bindings((String) null);
+
+            assertThat(b.getBindings()).isEmpty();
+        }
+
+        @Test
+        @DisplayName("empty if path does not exist")
+        void nonExistentDirectory() {
+            String path = "src/test/resources/non-existent";
+            Bindings b = new Bindings(path);
+
+            assertThat(b.getBindings()).isEmpty();
+        }
+
+        @Test
+        @DisplayName("throws exception if path is not a directory")
+        void nonDirectory() throws IOException {
+            String path = File.createTempFile("bindings", "").getPath();
+
+            assertThatIllegalArgumentException().isThrownBy(() -> new Bindings(path));
+        }
+
+        @Test
+        @DisplayName("populates content")
+        void construct() {
+            String path = "src/test/resources";
+            Bindings b = new Bindings(path);
+
+            assertThat(b.getBindings()).hasSize(2);
+        }
+
+    }
+
+    @Nested
+    @DisplayName("Content")
+    final class Content {
+
+        private final Bindings bindings = new Bindings(
+                new Binding("test-name-1", Paths.get("src/test/resources/test-name-1"),
+                        metadata("test-kind-1", "test-provider-1"), Collections.emptyMap()),
+                new Binding("test-name-2", Paths.get("src/test/resources/test-name-2"),
+                        metadata("test-kind-2", "test-provider-2"), Collections.emptyMap())
+        );
+
+        private Map<String, String> metadata(String kind, String provider) {
+            Map<String, String> metadata = new HashMap<>(2);
+            metadata.put("kind", kind);
+            metadata.put("provider", provider);
+            return metadata;
+        }
+
+        @Test
+        @DisplayName("returns content")
+        void getBindings() {
+            assertThat(bindings.getBindings()).hasSize(2);
+        }
+
+        @Test
+        @DisplayName("filters bindings by kind")
+        void filterBindingsByKind() {
+            assertThat(bindings.filterBindings("test-kind-1", null)).hasSize(1);
+        }
+
+        @Test
+        @DisplayName("filters bindings by provider")
+        void filterBindingsByProvider() {
+            assertThat(bindings.filterBindings(null, "test-provider-1")).hasSize(1);
+        }
+
+    }
+
+}

cnb-bindings/src/test/java/org/springframework/cloud/cnb/core/BindingsTests.java

@@ -1,82 +0,0 @@
-/*
- * Copyright 2020 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.cloud.cnb.core;
-
-import org.junit.jupiter.api.Test;
-
-import java.io.File;
-import java.io.IOException;
-import java.util.Collections;
-
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
-
-final class BindingsTests {
-
-    @Test
-    void constructFromNonExistentDirectory() {
-        String path = "src/test/resources/non-existent";
-        Bindings b = new Bindings(path);
-
-        assertThat(b.getBindings()).isEmpty();
-    }
-
-    @Test
-    void constructFromNonDirectory() throws IOException {
-        String path = File.createTempFile("bindings", "").getPath();
-
-        assertThatIllegalArgumentException().isThrownBy(() -> new Bindings(path));
-    }
-
-    @Test
-    void construct() {
-        String path = "src/test/resources";
-        Bindings b = new Bindings(path);
-
-        assertThat(b.getBindings()).hasSize(2);
-    }
-
-    @Test
-    void hasBindings() {
-        assertThat(Bindings.hasBindings(Collections.emptyMap())).isFalse();
-        assertThat(Bindings.hasBindings(Collections.singletonMap("CNB_BINDINGS", ""))).isTrue();
-    }
-
-    @Test
-    void getBindings() {
-        String path = "src/test/resources";
-        Bindings b = new Bindings(path);
-
-        assertThat(b.getBindings()).hasSize(2);
-    }
-
-    @Test
-    void findBindingsByKind() {
-        String path = "src/test/resources";
-        Bindings b = new Bindings(path);
-
-        assertThat(b.getBindings("test-kind-1", null)).hasSize(1);
-    }
-
-    @Test
-    void findBindingsByProvider() {
-        String path = "src/test/resources";
-        Bindings b = new Bindings(path);
-
-        assertThat(b.getBindings(null, "test-provider-1")).hasSize(1);
-    }
-
-}