diff --git a/src/CallableResolver.php b/src/CallableResolver.php
new file mode 100644
index 0000000..abee5dc
--- /dev/null
+++ b/src/CallableResolver.php
@@ -0,0 +1,121 @@
+<?php
+
+namespace Invoker;
+
+use Interop\Container\ContainerInterface;
+use Invoker\Exception\NotCallableException;
+
+/**
+ * Resolves a callable from a container.
+ *
+ * @author Matthieu Napoli <matthieu@mnapoli.fr>
+ */
+class CallableResolver
+{
+    /**
+     * @var ContainerInterface
+     */
+    private $container;
+
+    public function __construct(ContainerInterface $container)
+    {
+        $this->container = $container;
+    }
+
+    /**
+     * Resolve the given callable into a real PHP callable.
+     *
+     * @param callable|string|array $callable
+     *
+     * @return callable Real PHP callable.
+     *
+     * @throws NotCallableException
+     */
+    public function resolve($callable)
+    {
+        $callable = $this->resolveFromContainer($callable);
+
+        if (! is_callable($callable)) {
+            throw new NotCallableException(sprintf(
+                '%s is not a callable',
+                is_object($callable) ? 'Instance of ' . get_class($callable) : var_export($callable, true)
+            ));
+        }
+
+        return $callable;
+    }
+
+    /**
+     * @param callable|string|array $callable
+     * @return callable
+     * @throws NotCallableException
+     */
+    private function resolveFromContainer($callable)
+    {
+        $isStaticCallToNonStaticMethod = false;
+
+        // If it's already a callable there is nothing to do
+        if (is_callable($callable)) {
+            $isStaticCallToNonStaticMethod = $this->isStaticCallToNonStaticMethod($callable);
+            if (! $isStaticCallToNonStaticMethod) {
+                return $callable;
+            }
+        }
+
+        // The callable is a container entry name
+        if (is_string($callable)) {
+            if ($this->container->has($callable)) {
+                return $this->container->get($callable);
+            } else {
+                throw new NotCallableException(sprintf(
+                    '%s is neither a callable or a valid container entry',
+                    $callable
+                ));
+            }
+        }
+
+        // The callable is an array whose first item is a container entry name
+        // e.g. ['some-container-entry', 'methodToCall']
+        if (is_array($callable) && is_string($callable[0])) {
+            if ($this->container->has($callable[0])) {
+                $callable[0] = $this->container->get($callable[0]);
+                return $callable;
+            } elseif ($isStaticCallToNonStaticMethod) {
+                throw new NotCallableException(sprintf(
+                    'Cannot call %s::%s() because %s() is not a static method and "%s" is not a container entry',
+                    $callable[0],
+                    $callable[1],
+                    $callable[1],
+                    $callable[0]
+                ));
+            } else {
+                throw new NotCallableException(sprintf(
+                    'Cannot call %s on %s because it is not a class nor a valid container entry',
+                    $callable[1],
+                    $callable[0]
+                ));
+            }
+        }
+
+        // Unrecognized stuff, we let it fail later
+        return $callable;
+    }
+
+    /**
+     * Check if the callable represents a static call to a non-static method.
+     *
+     * @param mixed $callable
+     * @return bool
+     */
+    private function isStaticCallToNonStaticMethod($callable)
+    {
+        if (is_array($callable) && is_string($callable[0])) {
+            list($class, $method) = $callable;
+            $reflection = new \ReflectionMethod($class, $method);
+
+            return ! $reflection->isStatic();
+        }
+
+        return false;
+    }
+}
diff --git a/src/Invoker.php b/src/Invoker.php
index 83da882..1a49cff 100644
--- a/src/Invoker.php
+++ b/src/Invoker.php
@@ -30,10 +30,19 @@ class Invoker implements InvokerInterface
      */
     private $container;
 
+    /**
+     * @var CallableResolver|null
+     */
+    private $callableResolver;
+
     public function __construct(ParameterResolver $parameterResolver = null, ContainerInterface $container = null)
     {
         $this->parameterResolver = $parameterResolver ?: $this->createParameterResolver();
         $this->container = $container;
+
+        if ($container) {
+            $this->callableResolver = new CallableResolver($container);
+        }
     }
 
     /**
@@ -41,10 +50,16 @@ public function __construct(ParameterResolver $parameterResolver = null, Contain
      */
     public function call($callable, array $parameters = array())
     {
-        if ($this->container) {
-            $callable = $this->resolveCallableFromContainer($callable);
+        if ($this->callableResolver) {
+            $callable = $this->callableResolver->resolve($callable);
+        }
+
+        if (! is_callable($callable)) {
+            throw new NotCallableException(sprintf(
+                '%s is not a callable',
+                is_object($callable) ? 'Instance of ' . get_class($callable) : var_export($callable, true)
+            ));
         }
-        $this->assertIsCallable($callable);
 
         $callableReflection = CallableReflection::create($callable);
 
@@ -105,91 +120,11 @@ public function getContainer()
     }
 
     /**
-     * @param callable|string|array $callable
-     * @return callable
-     * @throws NotCallableException
+     * @return CallableResolver|null Returns null if no container was given in the constructor.
      */
-    private function resolveCallableFromContainer($callable)
+    public function getCallableResolver()
     {
-        $isStaticCallToNonStaticMethod = false;
-
-        // If it's already a callable there is nothing to do
-        if (is_callable($callable)) {
-            $isStaticCallToNonStaticMethod = $this->isStaticCallToNonStaticMethod($callable);
-            if (! $isStaticCallToNonStaticMethod) {
-                return $callable;
-            }
-        }
-
-        // The callable is a container entry name
-        if (is_string($callable)) {
-            if ($this->container->has($callable)) {
-                return $this->container->get($callable);
-            } else {
-                throw new NotCallableException(sprintf(
-                    '%s is neither a callable or a valid container entry',
-                    $callable
-                ));
-            }
-        }
-
-        // The callable is an array whose first item is a container entry name
-        // e.g. ['some-container-entry', 'methodToCall']
-        if (is_array($callable) && is_string($callable[0])) {
-            if ($this->container->has($callable[0])) {
-                $callable[0] = $this->container->get($callable[0]);
-                return $callable;
-            } elseif ($isStaticCallToNonStaticMethod) {
-                throw new NotCallableException(sprintf(
-                    'Cannot call %s::%s() because %s() is not a static method and "%s" is not a container entry',
-                    $callable[0],
-                    $callable[1],
-                    $callable[1],
-                    $callable[0]
-                ));
-            } else {
-                throw new NotCallableException(sprintf(
-                    'Cannot call %s on %s because it is not a class nor a valid container entry',
-                    $callable[1],
-                    $callable[0]
-                ));
-            }
-        }
-
-        // Unrecognized stuff, we let it fail later
-        return $callable;
-    }
-
-    /**
-     * @param callable $callable
-     * @throws NotCallableException
-     */
-    private function assertIsCallable($callable)
-    {
-        if (! is_callable($callable)) {
-            throw new NotCallableException(sprintf(
-                '%s is not a callable',
-                is_object($callable) ? 'Instance of ' . get_class($callable) : var_export($callable, true)
-            ));
-        }
-    }
-
-    /**
-     * Check if the callable represents a static call to a non-static method.
-     *
-     * @param mixed $callable
-     * @return bool
-     */
-    private function isStaticCallToNonStaticMethod($callable)
-    {
-        if (is_array($callable) && is_string($callable[0])) {
-            list($class, $method) = $callable;
-            $reflection = new \ReflectionMethod($class, $method);
-
-            return ! $reflection->isStatic();
-        }
-
-        return false;
+        return $this->callableResolver;
     }
 
     private function assertMandatoryParametersAreResolved($parameters, ReflectionFunctionAbstract $reflection)
diff --git a/tests/CallableResolverTest.php b/tests/CallableResolverTest.php
new file mode 100644
index 0000000..de98406
--- /dev/null
+++ b/tests/CallableResolverTest.php
@@ -0,0 +1,112 @@
+<?php
+
+namespace Invoker\Test;
+
+use Invoker\CallableResolver;
+use Invoker\Test\Mock\ArrayContainer;
+use Invoker\Test\Mock\CallableSpy;
+
+class CallableResolverTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @var CallableResolver
+     */
+    private $resolver;
+
+    /**
+     * @var ArrayContainer
+     */
+    private $container;
+
+    public function setUp()
+    {
+        $this->container = new ArrayContainer;
+        $this->resolver = new CallableResolver($this->container);
+    }
+
+    /**
+     * @test
+     */
+    public function resolves_function_callable()
+    {
+        $result = $this->resolver->resolve('strlen');
+
+        $this->assertSame(strlen('Hello world!'), $result('Hello world!'));
+    }
+
+    /**
+     * @test
+     */
+    public function resolves_namespaced_function_callable()
+    {
+        $result = $this->resolver->resolve(__NAMESPACE__ . '\foo');
+
+        $this->assertEquals('bar', $result());
+    }
+
+    /**
+     * @test
+     */
+    public function resolves_callable_from_container()
+    {
+        $callable = function () {};
+        $this->container->set('thing-to-call', $callable);
+
+        $this->assertSame($callable, $this->resolver->resolve('thing-to-call'));
+    }
+
+    /**
+     * @test
+     */
+    public function resolves_invokable_class_from_container()
+    {
+        $callable = new CallableSpy;
+        $this->container->set('Invoker\Test\Mock\CallableSpy', $callable);
+
+        $this->assertSame($callable, $this->resolver->resolve('Invoker\Test\Mock\CallableSpy'));
+    }
+
+    /**
+     * @test
+     */
+    public function resolves_method_call_service_from_container()
+    {
+        $fixture = new InvokerTestFixture;
+        $this->container->set('thing-to-call', $fixture);
+
+        $result = $this->resolver->resolve(array('thing-to-call', 'foo'));
+
+        $result();
+        $this->assertTrue($fixture->wasCalled);
+    }
+
+    /**
+     * @test
+     */
+    public function resolves_method_call_class_from_container()
+    {
+        $fixture = new InvokerTestFixture;
+        $this->container->set('Invoker\Test\InvokerTestFixture', $fixture);
+
+        $result = $this->resolver->resolve(array('Invoker\Test\InvokerTestFixture', 'foo'));
+
+        $result();
+        $this->assertTrue($fixture->wasCalled);
+    }
+
+    /**
+     * @test
+     * @expectedException \Invoker\Exception\NotCallableException
+     * @expectedExceptionMessage foo is neither a callable or a valid container entry
+     */
+    public function throws_resolving_non_callable_from_container()
+    {
+        $resolver = new CallableResolver(new ArrayContainer);
+        $resolver->resolve('foo');
+    }
+}
+
+function foo()
+{
+    return 'bar';
+}
diff --git a/tests/InvokerTest.php b/tests/InvokerTest.php
index f4e26bf..3c44c9c 100644
--- a/tests/InvokerTest.php
+++ b/tests/InvokerTest.php
@@ -282,6 +282,7 @@ class InvokerTestFixture
     public $wasCalled = false;
     public function foo()
     {
+        // Use this to make sure we are not called from a static context
         $this->wasCalled = true;
         return 'bar';
     }