From 0ec573f4c5705ecce51ebe637750301fa57e3d1f Mon Sep 17 00:00:00 2001
From: Louise Crow <louise.crow@gmail.com>
Date: Thu, 13 Mar 2014 17:43:33 +0000
Subject: Rename spec files so they're run by rake spec.

---
 spec/lib/confidence_intervals_spec.rb | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 spec/lib/confidence_intervals_spec.rb

(limited to 'spec/lib/confidence_intervals_spec.rb')

diff --git a/spec/lib/confidence_intervals_spec.rb b/spec/lib/confidence_intervals_spec.rb
new file mode 100644
index 000000000..cb8717f3d
--- /dev/null
+++ b/spec/lib/confidence_intervals_spec.rb
@@ -0,0 +1,30 @@
+require 'confidence_intervals'
+
+describe "ci_bounds" do
+
+  describe "when passed all successes" do
+    it "should never return a high CI above 1" do
+      ci = ci_bounds 16, 16, 0.01
+      ci[1].should be <= 1
+    end
+  end
+
+  describe "when passed all failures" do
+    it "should never return a low CI below 0" do
+      ci = ci_bounds 0, 10, 0.05
+      ci[0].should be >= 0
+    end
+  end
+
+  describe "when passed 4 out of 10 successes (with 0.05 power)" do
+    it "should return the correct Wilson's interval" do
+      # The expected results here were taken from an online
+      # calculator:
+      #   http://www.vassarstats.net/prop1.html
+      ci = ci_bounds 7, 10, 0.05
+      ci[0].should be_within(0.001).of(0.3968)
+      ci[1].should be_within(0.001).of(0.8922)
+    end
+  end
+
+end
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