1 files changed, 43 insertions, 0 deletions
diff --git a/spec/ruby/core/math/erfc_spec.rb b/spec/ruby/core/math/erfc_spec.rb
new file mode 100644
index 0000000000..21c9e246ff
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+++ b/spec/ruby/core/math/erfc_spec.rb
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+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes', __FILE__)
+
+# erfc is the complementary error function
+describe "Math.erfc" do
+  it "returns a float" do
+    Math.erf(1).should be_kind_of(Float)
+  end
+
+  it "returns the complementary error function of the argument" do
+    Math.erfc(0).should be_close(1.0, TOLERANCE)
+    Math.erfc(1).should be_close(0.157299207050285, TOLERANCE)
+    Math.erfc(-1).should be_close(1.84270079294971, TOLERANCE)
+    Math.erfc(0.5).should be_close(0.479500122186953, TOLERANCE)
+    Math.erfc(-0.5).should be_close(1.52049987781305, TOLERANCE)
+    Math.erfc(10000).should be_close(0.0, TOLERANCE)
+    Math.erfc(-10000).should be_close(2.0, TOLERANCE)
+    Math.erfc(0.00000000000001).should be_close(0.999999999999989, TOLERANCE)
+    Math.erfc(-0.00000000000001).should be_close(1.00000000000001, TOLERANCE)
+  end
+
+  it "raises a TypeError if the argument cannot be coerced with Float()" do
+    lambda { Math.erfc("test") }.should raise_error(TypeError)
+  end
+
+  it "returns NaN given NaN" do
+    Math.erfc(nan_value).nan?.should be_true
+  end
+
+  it "raises a TypeError if the argument is nil" do
+    lambda { Math.erfc(nil) }.should raise_error(TypeError)
+  end
+
+  it "accepts any argument that can be coerced with Float()" do
+    Math.erfc(MathSpecs::Float.new).should be_close(0.157299207050285, TOLERANCE)
+  end
+end
+
+describe "Math#erfc" do
+  it "is accessible as a private instance method" do
+    IncludesMath.new.send(:erf, 3.1415).should be_close(0.999991118444483, TOLERANCE)
+  end
+end