1 files changed, 68 insertions, 0 deletions
diff --git a/spec/ruby/library/matrix/empty_spec.rb b/spec/ruby/library/matrix/empty_spec.rb
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+++ b/spec/ruby/library/matrix/empty_spec.rb
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+require File.expand_path('../../../spec_helper', __FILE__)
+require File.expand_path('../fixtures/classes', __FILE__)
+require 'matrix'
+
+describe "Matrix#empty?" do
+  it "returns true when the Matrix is empty" do
+    Matrix[ ].empty?.should be_true
+    Matrix[ [], [], [] ].empty?.should be_true
+    Matrix[ [], [], [] ].transpose.empty?.should be_true
+  end
+
+  it "returns false when the Matrix has elements" do
+    Matrix[ [1, 2] ].empty?.should be_false
+    Matrix[ [1], [2] ].empty?.should be_false
+  end
+
+  it "doesn't accept any parameter" do
+    lambda{
+      Matrix[ [1, 2] ].empty?(42)
+    }.should raise_error(ArgumentError)
+  end
+end
+
+describe "Matrix.empty" do
+  it "returns an empty matrix of the requested size" do
+    m = Matrix.empty(3, 0)
+    m.row_size.should == 3
+    m.column_size.should == 0
+
+    m = Matrix.empty(0, 3)
+    m.row_size.should == 0
+    m.column_size.should == 3
+  end
+
+  it "has arguments defaulting to 0" do
+    Matrix.empty.should == Matrix.empty(0, 0)
+    Matrix.empty(42).should == Matrix.empty(42, 0)
+  end
+
+  it "does not accept more than two parameters" do
+    lambda{
+      Matrix.empty(1, 2, 3)
+    }.should raise_error(ArgumentError)
+  end
+
+  it "raises an error if both dimensions are > 0" do
+    lambda{
+      Matrix.empty(1, 2)
+    }.should raise_error(ArgumentError)
+  end
+
+  it "raises an error if any dimension is < 0" do
+    lambda{
+      Matrix.empty(-2, 0)
+    }.should raise_error(ArgumentError)
+
+    lambda{
+      Matrix.empty(0, -2)
+    }.should raise_error(ArgumentError)
+  end
+
+end
+
+describe "for a subclass of Matrix" do
+  it "returns an instance of that subclass" do
+    MatrixSub.empty(0, 1).should be_an_instance_of(MatrixSub)
+  end
+end