diff --git a/Gemfile.lock b/Gemfile.lock
index f53e996..af661ec 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -8,9 +8,20 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
+    Ascii85 (1.1.0)
+    afm (0.2.2)
     diff-lcs (1.5.1)
+    hashery (2.1.2)
     matrix (0.4.2)
     pdf-core (0.9.0)
+    pdf-inspector (1.3.0)
+      pdf-reader (>= 1.0, < 3.0.a)
+    pdf-reader (2.12.0)
+      Ascii85 (~> 1.0)
+      afm (~> 0.2.1)
+      hashery (~> 2.0)
+      ruby-rc4
+      ttfunk
     prawn (2.4.0)
       pdf-core (~> 0.9.0)
       ttfunk (~> 1.7)
@@ -28,6 +39,7 @@ GEM
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.13.0)
     rspec-support (3.13.0)
+    ruby-rc4 (0.1.5)
     ttfunk (1.7.0)
 
 PLATFORMS
@@ -35,6 +47,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
+  pdf-inspector (~> 1.0)
   phlex-pdf!
   rake (~> 13.0)
   rspec (~> 3.0)
diff --git a/lib/phlex/pdf.rb b/lib/phlex/pdf.rb
index 9284cec..dff299b 100644
--- a/lib/phlex/pdf.rb
+++ b/lib/phlex/pdf.rb
@@ -10,7 +10,7 @@ class PDF
 
     def document = @document
 
-    def call(document = self.class.blank, &block)
+    def call(document, &block)
       @document = document
       around_template do
         if block_given?
@@ -45,8 +45,7 @@ def after_template
     end
 
     def to_pdf(...)
-      call
-      @document.render(...)
+      self.class.blank.tap{ |doc| call doc }.render(...)
     end
 
     def yield_content(&block)
diff --git a/phlex-pdf.gemspec b/phlex-pdf.gemspec
index 078c4d4..05d0448 100644
--- a/phlex-pdf.gemspec
+++ b/phlex-pdf.gemspec
@@ -36,6 +36,8 @@ Gem::Specification.new do |spec|
   spec.add_dependency "prawn", "~> 2.0"
   spec.add_dependency "matrix", "~> 0.4"
 
+  spec.add_development_dependency("pdf-inspector", "~> 1.0")
+
   # For more information and examples about making a new gem, check out our
   # guide at: https://bundler.io/guides/creating_gem.html
 end
diff --git a/spec/phlex/pdf_spec.rb b/spec/phlex/pdf_spec.rb
index 928c222..a6d1804 100644
--- a/spec/phlex/pdf_spec.rb
+++ b/spec/phlex/pdf_spec.rb
@@ -87,7 +87,18 @@ def view_template
 end
 
 RSpec.describe Phlex::PDF do
+  let(:pages) do
+    PDF::Inspector::Page.analyze(PDFDocument.new.to_pdf).pages
+  end
+
   it "generates a PDF" do
-    PDFDocument.new.to_pdf
+    expect(pages.size).to eq(3)
+    expect(pages[0][:strings]).to include("Hi", "There")
+    expect(pages[1][:strings]).to include("Friendly", "Pal")
+    expect(pages[2][:strings]).to include("Whats", "Up")
+
+    pages.each do |page|
+      expect(page[:strings]).to include("Header", "Rendered from Proc.new", "Rendered from proc", "Rendered from lambda", "Rendered from ->", "Rendered from Method", "Rendered from lambda", "Rendered from ->", "Rendered from Method", "Hello Brad", "Danger!", "Don't Panic!")
+    end
   end
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 135a94f..c457671 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "phlex/pdf"
+require "pdf/inspector"
 
 RSpec.configure do |config|
   # Enable flags like --only-failures and --next-failure