speed up test runs by only booting docker once in a run block per test case

spec/simple_spec.rb

@@ -59,6 +59,7 @@ RSpec.describe "Simple" do
     let(:name) { "routes" }
 
     it "should support custom routes" do
+      app.run do
         response = app.get("/foo.html")
         expect(response.code).to eq("200")
         expect(response.body.chomp).to eq("hello world")
@@ -72,6 +73,7 @@ RSpec.describe "Simple" do
         expect(response.body.chomp).to eq("hello from route")
       end
     end
+  end
 
   describe "redirects" do
     let(:name) { "redirects" }
@@ -158,6 +160,7 @@ STATIC_JSON
     let(:name) { "custom_headers" }
 
     it "should return the respected headers only for the path specified" do
+      app.run do
         response = app.get("/")
         expect(response["cache-control"]).to eq("no-cache")
         expect(response.code).to eq("200")
@@ -168,11 +171,13 @@ STATIC_JSON
         expect(response.code).to eq("200")
         expect(response.body.chomp).to eq("foo")
       end
+    end
 
     describe "wildcard paths" do
       let(:name) { "custom_headers_wildcard" }
 
       it "should add the headers" do
+        app.run do
           response = app.get("/cache/")
           expect(response["Cache-Control"]).to eq("max-age=38400")
           expect(response.code).to eq("200")
@@ -184,6 +189,7 @@ STATIC_JSON
           expect(response.body.chomp).to eq("index")
         end
       end
+    end
 
     describe "redirect" do
       let(:name) { "custom_headers_redirect" }
@@ -199,6 +205,7 @@ STATIC_JSON
       let(:name) { "custom_headers_clean_urls" }
 
       it "should add the headers" do
+        app.run do
           response = app.get("/foo")
           expect(response.code).to eq("200")
           expect(response.body.chomp).to eq("foo")
@@ -209,6 +216,7 @@ STATIC_JSON
           expect(response.body.chomp).to eq("bar")
           expect(response["X-Header"]).to be_nil
         end
+      end
 
       it "should not add headers for .html urls" do
         response = app.get("/foo.html")
@@ -221,6 +229,7 @@ STATIC_JSON
       let(:name) { "custom_headers_routes" }
 
       it "should add headers" do
+        app.run do
           response = app.get("/active")
           expect(response.code).to eq("200")
           expect(response.body.chomp).to eq("index")
@@ -232,6 +241,7 @@ STATIC_JSON
           expect(response["X-Header"]).to be_nil
         end
       end
+    end
 
     describe "proxies" do
       include PathHelper
@@ -269,6 +279,7 @@ STATIC_JSON
       end
 
       it "should proxy requests" do
+        app.run do
           response = app.get("/api/bar/")
           expect(response.code).to eq("200")
           expect(response.body.chomp).to eq("api")
@@ -281,4 +292,5 @@ STATIC_JSON
         end
       end
     end
+  end
 end

spec/support/app_runner.rb

@@ -20,6 +20,7 @@ class AppRunner
   CONTAINER_PORT = "3000"
 
   def initialize(fixture, env = nil, debug = false)
+    @run       = false
     @debug     = debug
     @container = Docker::Container.create(
       'Image'      => BuildpackBuilder::TAG,
@@ -39,6 +40,8 @@ class AppRunner
   end
 
   def run
+    @run       = true
+    retn       = nil
     latch      = Concurrent::CountDownLatch.new(1)
     run_thread = Thread.new {
       latch.wait(0.5)
@@ -51,33 +54,38 @@ class AppRunner
       end
     }
 
-    run_thread.join
+    retn = run_thread.value
     @container.stop
     container_thread.join
+    @run = false
+
+    retn
   end
 
   def get(path, max_retries = 5)
-    response = nil
+    if @run
+      response = get_retry(path, max_retries)
+    else
+      run { get_retry(path, max_retries) }
+    end
+  end
+
+  def destroy
+    @container.delete(force: true) unless @debug
+  end
 
-    run do
+  private
+  def get_retry(path, max_retries)
     network_retry(max_retries) do
       uri = URI("#{path}")
       uri.host   = HOST_IP   if uri.host.nil?
       uri.port   = HOST_PORT if (uri.host == HOST_IP && uri.port != HOST_PORT) || uri.port.nil?
       uri.scheme = "http"    if uri.scheme.nil?
 
-        response = Net::HTTP.get_response(URI(uri.to_s))
+      Net::HTTP.get_response(URI(uri.to_s))
     end
   end
 
-    response
-  end
-
-  def destroy
-    @container.delete(force: true) unless @debug
-  end
-
-  private
   def network_retry(max_retries, retry_count = 0)
     yield
   rescue Errno::ECONNRESET, EOFError