From dfc4ad95b3506c7b52ead6cf1e5f34d3a13dbb56 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Aslak=20Helles=C3=B8y?= <aslak.hellesoy@gmail.com>
Date: Wed, 4 Oct 2017 08:31:17 +0100
Subject: [PATCH] Add a spike based on Rantly

---
 lib/coordinate.rb   |  5 +++--
 spec/shouty_spec.rb | 21 +++++++++++++++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)
 create mode 100644 spec/shouty_spec.rb

diff --git a/lib/coordinate.rb b/lib/coordinate.rb
index 49cdb29..01fd546 100644
--- a/lib/coordinate.rb
+++ b/lib/coordinate.rb
@@ -7,7 +7,8 @@ def initialize(x, y)
   end
 
   def distance_from(other)
-    # TODO: actually caluculate distance. I think we need to use the Pythagorean theorem?
-    0
+    dx = other.x - x
+    dy = other.y - y
+    Math.sqrt(dx*dx+dy*dy)
   end
 end
diff --git a/spec/shouty_spec.rb b/spec/shouty_spec.rb
new file mode 100644
index 0000000..38ea4b4
--- /dev/null
+++ b/spec/shouty_spec.rb
@@ -0,0 +1,21 @@
+require 'rantly/rspec_extensions'
+require 'shouty'
+require 'coordinate'
+
+describe Shouty do
+  it "only tranmits shouts within 1000m" do
+    property_of {
+      shouter_loc  = Coordinate.new(*Rantly(2) { range(0, 2000) })
+      listener_loc = Coordinate.new(*Rantly(2) { range(0, 2000) })
+      guard shouter_loc.distance_from(listener_loc) < 1000
+
+      [shouter_loc, listener_loc]
+    }.check { |shouter_loc, listener_loc|
+      shouty = Shouty.new
+      shouty.set_location('shouter', shouter_loc)
+      shouty.set_location('listener', listener_loc)
+      shouty.shout('shouter', listener_loc)
+      expect(shouty.messages_heard_by('listener').length).to eq(1)
+    }
+  end
+end