diff --git a/.vscode/launch.json b/.vscode/launch.json
index 0aecd80..a0047db 100644
--- a/.vscode/launch.json
+++ b/.vscode/launch.json
@@ -5,75 +5,13 @@
   "version": "0.2.0",
   "configurations": [
     {
-      "name": "Launch index.html",
-      "type": "chrome",
+      "type": "rdbg",
+      "name": "Rspec",
       "request": "launch",
-      "breakOnLoad": true,
-      "sourceMapPathOverrides": {
-        "webRoot": "${workspaceRoot}"
-      },
-      "file": "${workspaceRoot}/index.html"
-    },
-    {
-      "name": "Debug Local File",
-      "type": "Ruby",
-      "request": "launch",
-      "cwd": "${workspaceRoot}",
-      "program": "${workspaceRoot}/exe/cpp_dependency_graph",
-      "useBundler": true,
-      "pathToBundler": "C:/tools/ruby25/bin/bundle.bat",
-      "pathToRDebugIDE": "C:/tools/ruby25/bin/rdebug-ide.bat",
-      "showDebuggerOutput": true,
-      "args": ["visualise_components", "-r", "../TileDB"]
-    },
-    {
-      "name": "Listen for rdebug-ide",
-      "type": "Ruby",
-      "request": "attach",
-      "cwd": "${workspaceRoot}",
-      "remoteHost": "127.0.0.1",
-      "remotePort": "1234",
-      "remoteWorkspaceRoot": "${workspaceRoot}"
-    },
-    {
-      "name": "Rails server",
-      "type": "Ruby",
-      "request": "launch",
-      "cwd": "${workspaceRoot}",
-      "program": "${workspaceRoot}/bin/rails",
-      "args": [
-        "server"
-      ]
-    },
-    {
-      "name": "RSpec - all",
-      "type": "Ruby",
-      "request": "launch",
-      "cwd": "${workspaceRoot}",
-      "program": "C:/tools/ruby25/bin/rspec",
-      "args": [
-        "-I",
-        "${workspaceRoot}"
-      ]
-    },
-    {
-      "name": "RSpec - active spec file only",
-      "type": "Ruby",
-      "request": "launch",
-      "cwd": "${workspaceRoot}",
-      "program": "C:/tools/ruby25/bin/rspec",
-      "args": [
-        "-I",
-        "${workspaceRoot}",
-        "${file}"
-      ]
-    },
-    {
-      "name": "Cucumber",
-      "type": "Ruby",
-      "request": "launch",
-      "cwd": "${workspaceRoot}",
-      "program": "${workspaceRoot}/bin/cucumber"
+      "command": "bundle exec rspec",
+      "script": "${file}:${lineNumber}",
+      "args": [],
+      "askParameters": false
     }
   ]
-}
\ No newline at end of file
+}
diff --git a/lib/cpp_dependency_graph/include_component_dependency_graph.rb b/lib/cpp_dependency_graph/include_component_dependency_graph.rb
index b623d55..a542eaf 100644
--- a/lib/cpp_dependency_graph/include_component_dependency_graph.rb
+++ b/lib/cpp_dependency_graph/include_component_dependency_graph.rb
@@ -23,7 +23,6 @@ def all_cyclic_links
 
   def links(component_name)
     component = @project.source_component(component_name)
-    p component
     source_files = component.source_files
     external_includes = @project.external_includes(component)
     source_files.map do |file|
diff --git a/lib/cpp_dependency_graph/include_dependency.rb b/lib/cpp_dependency_graph/include_dependency.rb
new file mode 100644
index 0000000..c4b3734
--- /dev/null
+++ b/lib/cpp_dependency_graph/include_dependency.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+# Represents a #include in a source file
+class IncludeDependency
+  def initialize(raw_include)
+    @raw_include = raw_include
+    p = Pathname.new(@raw_include)
+    @dir_name = p.dirname
+    @basename = p.basename.to_s
+    @absolute_include = @dir_name == Pathname.new('.')
+  end
+
+  def relative?
+    !@absolute_include
+  end
+
+  def absolute?
+    @absolute_include
+  end
+
+  def component
+    return @dir_name.to_s unless absolute?
+
+    ''
+  end
+
+  def ==(other)
+    raw_include == other.raw_include
+  end
+  alias eql? ==
+
+  def hash
+    [self.class, @raw_include].hash
+  end
+
+  attr_reader :basename, :raw_include
+end
diff --git a/lib/cpp_dependency_graph/include_to_component_resolver.rb b/lib/cpp_dependency_graph/include_to_component_resolver.rb
index 4e8f5f4..8b00926 100644
--- a/lib/cpp_dependency_graph/include_to_component_resolver.rb
+++ b/lib/cpp_dependency_graph/include_to_component_resolver.rb
@@ -18,9 +18,12 @@ def external_includes(component)
   end
 
   def component_for_include(include)
-    return '' unless source_files.key?(include)
+    return '' unless source_files.key?(include.basename)
 
-    @component_include_map_cache[include] = component_for_include_private(include) unless @component_include_map_cache.key?(include)
+    component = component_for_include_private(include.basename) unless @component_include_map_cache.key?(include.basename)
+    return '' if !include.component.empty? and include.component != component
+
+    @component_include_map_cache[include] = component
     @component_include_map_cache[include]
   end
 
diff --git a/lib/cpp_dependency_graph/project.rb b/lib/cpp_dependency_graph/project.rb
index 1cdc637..b00d714 100644
--- a/lib/cpp_dependency_graph/project.rb
+++ b/lib/cpp_dependency_graph/project.rb
@@ -37,7 +37,10 @@ def source_files
 
   def dependencies(component)
     # TODO: This is repeating the same work twice! component_for_include is called when calling external_includes
-    external_includes(component).map { |include| @include_resolver.component_for_include(include) }.reject(&:empty?).uniq
+    external_includes_component = external_includes(component)
+    external_includes_component.map do |include|
+      @include_resolver.component_for_include(include)
+    end.reject(&:empty?).uniq
   end
 
   def external_includes(component)
diff --git a/lib/cpp_dependency_graph/source_component.rb b/lib/cpp_dependency_graph/source_component.rb
index 8658984..151dc22 100644
--- a/lib/cpp_dependency_graph/source_component.rb
+++ b/lib/cpp_dependency_graph/source_component.rb
@@ -1,6 +1,9 @@
 # frozen_string_literal: true
 
+require 'pathname'
+
 require_relative 'config'
+require_relative 'include_dependency'
 require_relative 'directory_parser'
 require_relative 'source_file'
 
@@ -24,13 +27,17 @@ def source_files
   end
 
   def includes
-    @includes ||= source_files.flat_map(&:includes).uniq.map { |include| File.basename(include) }
+    @includes ||= source_files.flat_map(&:includes).uniq.map { |f| IncludeDependency.new(f) }.uniq
   end
 
   def loc
     @loc ||= source_files.inject(0) { |total_loc, file| total_loc + file.loc }
   end
 
+  def exists?
+    File.exist?(@path)
+  end
+
   private
 
   def parse_source_files(extensions)
diff --git a/lib/cpp_dependency_graph/source_file.rb b/lib/cpp_dependency_graph/source_file.rb
index 9fa9feb..9b966b6 100644
--- a/lib/cpp_dependency_graph/source_file.rb
+++ b/lib/cpp_dependency_graph/source_file.rb
@@ -34,6 +34,10 @@ def loc
     @loc ||= file_contents.lines.count
   end
 
+  def exists?
+    File.exist?(path)
+  end
+
   private
 
   def all_includes
diff --git a/spec/test/example_project/Engine/Engine.cpp b/spec/test/example_project/Engine/Engine.cpp
index 8076f7a..a1f0123 100644
--- a/spec/test/example_project/Engine/Engine.cpp
+++ b/spec/test/example_project/Engine/Engine.cpp
@@ -1,3 +1,2 @@
 #include "DataAccess/DA.h"
 #include "Engine.h"
-
diff --git a/spec/test/include_dependency_spec.rb b/spec/test/include_dependency_spec.rb
new file mode 100644
index 0000000..70b780a
--- /dev/null
+++ b/spec/test/include_dependency_spec.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require 'cpp_dependency_graph/include_dependency'
+
+RSpec.describe IncludeDependency do
+  it 'relative? returns false for an absolute include' do
+    i = IncludeDependency.new('Engine.h')
+    expect(i.relative?).to be false
+    expect(i.absolute?).to be true
+  end
+
+  it 'relative? returns true for a relative include' do
+    i = IncludeDependency.new('Engine/Engine.h')
+    expect(i.relative?).to be true
+    expect(i.absolute?).to be false
+  end
+
+  it 'component returns empty for a relative include' do
+    i = IncludeDependency.new('Engine.h')
+    expect(i.component).to eq('')
+  end
+
+  it 'component returns parent directory for a relative include' do
+    i = IncludeDependency.new('Engine/Engine.h')
+    expect(i.component).to eq('Engine')
+  end
+
+  it 'returns the correct basename' do
+    i = IncludeDependency.new('Engine/Engine.h')
+    expect(i.basename).to eq('Engine.h')
+  end
+
+  it 'compares correctly against other instances' do
+    i1 = IncludeDependency.new('Engine/Engine.h')
+    i2 = IncludeDependency.new('Engine/Engine.h')
+    expect(i1).to eq(i2)
+  end
+end
diff --git a/spec/test/project_spec.rb b/spec/test/project_spec.rb
index 21e03ee..94d48e8 100644
--- a/spec/test/project_spec.rb
+++ b/spec/test/project_spec.rb
@@ -25,17 +25,17 @@
     expect(component.source_files.size).to eq(0)
   end
 
-  it 'returns dependencies of component' do
-    project = Project.new('spec/test/example_project')
-    component = project.source_component('Engine')
-    dependencies = project.dependencies(component)
-    expect(dependencies).to include('Framework', 'UI', 'DataAccess')
-  end
-
   it 'all source files of project' do
     project = Project.new('spec/test/example_project')
     source_files = project.source_files.values.map(&:basename)
     expect(source_files).to contain_exactly('DA.h', 'Display.cpp', 'Display.h', 'Engine.cpp', 'Engine.h', 'Engine.h',
                                             'OldEngine.h', 'System.cpp', 'System.h', 'framework.h', 'main.cpp')
   end
+
+  it 'returns dependencies of component' do
+    project = Project.new('spec/test/example_project')
+    component = project.source_component('Engine')
+    dependencies = project.dependencies(component)
+    expect(dependencies).to include('Framework', 'UI', 'DataAccess')
+  end
 end
diff --git a/spec/test/source_component_spec.rb b/spec/test/source_component_spec.rb
index dd60f66..d759ce2 100644
--- a/spec/test/source_component_spec.rb
+++ b/spec/test/source_component_spec.rb
@@ -3,6 +3,16 @@
 require 'cpp_dependency_graph/source_component'
 
 RSpec.describe SourceComponent do
+  it 'exists? returns true for a valid component' do
+    component = SourceComponent.new('spec/test/example_project/Engine')
+    expect(component.exists?).to be true
+  end
+
+  it 'exists? returns false for a valid component' do
+    component = SourceComponent.new('spec/test/example_project/Engine2')
+    expect(component.exists?).to be false
+  end
+
   it 'has a name attribute that matches the directory' do
     component = SourceComponent.new('spec/test/example_project/Engine')
     expect(component.name).to eq('Engine')
@@ -18,9 +28,11 @@
     expect(source_file_names).to contain_exactly('Engine.cpp', 'Engine.h', 'OldEngine.h')
   end
 
-  it 'has an includes attribute' do
+  it 'outputs the correct includes for component' do
     component = SourceComponent.new('spec/test/example_project/Engine')
-    expect(component.includes).to contain_exactly('framework.h', 'Display.h', 'DA.h', 'Engine.h')
+    expect(component.includes).to contain_exactly(an_object_having_attributes(basename: 'framework.h'),
+                                                  an_object_having_attributes(basename: 'Display.h'), an_object_having_attributes(basename: 'DA.h'),
+                                                  an_object_having_attributes(basename: 'Engine.h'))
   end
 
   it 'has a loc (lines of code) attribute' do
diff --git a/spec/test/source_file_spec.rb b/spec/test/source_file_spec.rb
index 7fa1ae2..3dd764a 100644
--- a/spec/test/source_file_spec.rb
+++ b/spec/test/source_file_spec.rb
@@ -32,4 +32,14 @@
     source_file = SourceFile.new('spec/test/example_project/Engine/Engine.cpp')
     expect(source_file.loc).to be > 0
   end
+
+  it 'exists? returns true for a file that exists' do
+    source_file = SourceFile.new('spec/test/example_project/Engine/Engine.cpp')
+    expect(source_file.exists?).to be true
+  end
+
+  it 'exists? returns false for a file that does not exist' do
+    source_file = SourceFile.new('spec/test/example_project/Engine/Engine2.cpp')
+    expect(source_file.exists?).to be false
+  end
 end