Add variable() accessor

ChangeLog.md

@@ -5,6 +5,8 @@ AWS Lambda change log
 
 ## 1.1.0 / 2021-08-28
 
+* Added accessor for environment varibales, `Environment::variable()`
+  (@thekid)
 * Added accessor for temporary directory, `Environment::tempDir()`
   (@thekid)
 * Added accessor for environment root path, `Environment::taskroot()`

src/main/php/com/amazon/aws/lambda/Environment.class.php

@@ -35,6 +35,16 @@ public function tempDir(): Path {
     return new Path(sys_get_temp_dir());
   }
 
+  /**
+   * Returns a given environment variable
+   *
+   * @param  string $name
+   * @return ?string
+   */
+  public function variable($name) {
+    return $_ENV[$name] ?? null;
+  }
+
   /**
    * Writes a trace message
    *

src/test/php/com/amazon/aws/lambda/unittest/EnvironmentTest.class.php

@@ -30,6 +30,18 @@ public function tempDir() {
     Assert::instance(Path::class, (new Environment('.'))->tempDir());
   }
 
+  #[Test]
+  public function variable() {
+    $_ENV['TEST']= 'true';
+    Assert::equals('true', (new Environment('.'))->variable('TEST'));
+  }
+
+  #[Test]
+  public function non_existant_variable() {
+    unset($_ENV['TEST']);
+    Assert::null((new Environment('.'))->variable('TEST'));
+  }
+
   #[Test]
   public function trace() {
     $stream= new MemoryOutputStream();