1 files changed, 29 insertions, 0 deletions
diff --git a/spec/ruby/library/date/prev_month_spec.rb b/spec/ruby/library/date/prev_month_spec.rb
new file mode 100644
index 0000000000..3d0d1d437d
--- /dev/null
+++ b/spec/ruby/library/date/prev_month_spec.rb
@@ -0,0 +1,29 @@
+require_relative '../../spec_helper'
+require 'date'
+
+describe "Date#prev_month" do
+  it "returns previous month" do
+    d = Date.new(2000, 9, 1).prev_month
+    d.should == Date.new(2000, 8, 1)
+  end
+
+  it "returns three months ago" do
+    d = Date.new(2000, 10, 1).prev_month(3)
+    d.should == Date.new(2000, 7, 1)
+  end
+
+  it "returns three months ago across years" do
+    d = Date.new(2000, 1, 1).prev_month(3)
+    d.should == Date.new(1999, 10, 1)
+  end
+
+  it "returns last day of month two months ago" do
+    d = Date.new(2000, 3, 31).prev_month(2)
+    d.should == Date.new(2000, 1, 31)
+  end
+
+  it "returns last day of previous month when same day does not exist" do
+    d = Date.new(2001, 3, 30).prev_month
+    d.should == Date.new(2001, 2, 28)
+  end
+end