1 files changed, 55 insertions, 0 deletions
diff --git a/spec/ruby/core/complex/to_s_spec.rb b/spec/ruby/core/complex/to_s_spec.rb
new file mode 100644
index 0000000000..ceccffe470
--- /dev/null
+++ b/spec/ruby/core/complex/to_s_spec.rb
@@ -0,0 +1,55 @@
+require_relative '../../spec_helper'
+require_relative '../numeric/fixtures/classes'
+
+describe "Complex#to_s" do
+  describe "when self's real component is 0" do
+    it "returns both the real and imaginary component even when the real is 0" do
+      Complex(0, 5).to_s.should == "0+5i"
+      Complex(0, -3.2).to_s.should == "0-3.2i"
+    end
+  end
+
+  it "returns self as String" do
+    Complex(1, 5).to_s.should == "1+5i"
+    Complex(-2.5, 1.5).to_s.should == "-2.5+1.5i"
+
+    Complex(1, -5).to_s.should == "1-5i"
+    Complex(-2.5, -1.5).to_s.should == "-2.5-1.5i"
+
+    # Guard against the Mathn library
+    guard -> { !defined?(Math.rsqrt) } do
+      Complex(1, 0).to_s.should == "1+0i"
+      Complex(1, -0).to_s.should == "1+0i"
+    end
+  end
+
+  it "returns 1+0.0i for Complex(1, 0.0)" do
+    Complex(1, 0.0).to_s.should == "1+0.0i"
+  end
+
+  it "returns 1-0.0i for Complex(1, -0.0)" do
+    Complex(1, -0.0).to_s.should == "1-0.0i"
+  end
+
+  it "returns 1+Infinity*i for Complex(1, Infinity)" do
+    Complex(1, infinity_value).to_s.should == "1+Infinity*i"
+  end
+
+  it "returns 1-Infinity*i for Complex(1, -Infinity)" do
+    Complex(1, -infinity_value).to_s.should == "1-Infinity*i"
+  end
+
+  it "returns 1+NaN*i for Complex(1, NaN)" do
+    Complex(1, nan_value).to_s.should == "1+NaN*i"
+  end
+
+  it "treats real and imaginary parts as strings" do
+    real = NumericSpecs::Subclass.new
+    # + because of https://bugs.ruby-lang.org/issues/20337
+    real.should_receive(:to_s).and_return(+"1")
+    imaginary = NumericSpecs::Subclass.new
+    imaginary.should_receive(:to_s).and_return("2")
+    imaginary.should_receive(:<).any_number_of_times.and_return(false)
+    Complex(real, imaginary).to_s.should == "1+2i"
+  end
+end