RSpec - 匹配器

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如果你还记得我们最初的 Hello World 示例，它包含一行如下所示的代码 -

expect(message).to eq "Hello World!"

关键字 eql 是一个 **RSpec** “匹配器”。在这里，我们将介绍 RSpec 中的其他类型的匹配器。

相等性/同一性匹配器

用于测试对象或值相等性的匹配器。

示例

describe "An example of the equality Matchers" do 

   it "should show how the equality Matchers work" do 
      a = "test string" 
      b = a 
      
      # The following Expectations will all pass 
      expect(a).to eq "test string" 
      expect(a).to eql "test string" 
      expect(a).to be b 
      expect(a).to equal b 
   end
   
end

当以上代码执行时，将产生以下输出。秒数在您的计算机上可能略有不同 -

.
Finished in 0.036 seconds (files took 0.11901 seconds to load)
1 example, 0 failures

比较匹配器

用于比较两个值的匹配器。

示例

describe "An example of the comparison Matchers" do

   it "should show how the comparison Matchers work" do
      a = 1
      b = 2
      c = 3		
      d = 'test string'
      
      # The following Expectations will all pass
      expect(b).to be > a
      expect(a).to be >= a 
      expect(a).to be < b 
      expect(b).to be <= b 
      expect(c).to be_between(1,3).inclusive 
      expect(b).to be_between(1,3).exclusive 
      expect(d).to match /TEST/i 
   end
   
end

当以上代码执行时，将产生以下输出。秒数在您的计算机上可能略有不同 -

. 
Finished in 0.013 seconds (files took 0.11801 seconds to load) 
1 example, 0 failures

类/类型匹配器

用于测试对象类型或类的匹配器。

示例

describe "An example of the type/class Matchers" do
 
   it "should show how the type/class Matchers work" do
      x = 1 
      y = 3.14 
      z = 'test string' 
      
      # The following Expectations will all pass
      expect(x).to be_instance_of Fixnum 
      expect(y).to be_kind_of Numeric 
      expect(z).to respond_to(:length) 
   end
   
end

当以上代码执行时，将产生以下输出。秒数在您的计算机上可能略有不同 -

. 
Finished in 0.002 seconds (files took 0.12201 seconds to load) 
1 example, 0 failures

真/假/空匹配器

用于测试值是否为真、假或空。

示例

describe "An example of the true/false/nil Matchers" do
   it "should show how the true/false/nil Matchers work" do
      x = true 
      y = false 
      z = nil 
      a = "test string" 
      
      # The following Expectations will all pass
      expect(x).to be true 
      expect(y).to be false 
      expect(a).to be_truthy 
      expect(z).to be_falsey 
      expect(z).to be_nil 
   end 
end

当以上代码执行时，将产生以下输出。秒数在您的计算机上可能略有不同 -

. 
Finished in 0.003 seconds (files took 0.12301 seconds to load) 
1 example, 0 failures

用于测试代码块何时引发错误的匹配器。

错误匹配器

示例

将以下代码保存到名为 **error_matcher_spec.rb** 的文件中，并使用以下命令运行它 - **rspec error_matcher_spec.rb**。

describe "An example of the error Matchers" do 
   it "should show how the error Matchers work" do 
      
      # The following Expectations will all pass 
      expect { 1/0 }.to raise_error(ZeroDivisionError)
      expect { 1/0 }.to raise_error("divided by 0") 
      expect { 1/0 }.to raise_error("divided by 0", ZeroDivisionError) 
   end 
end

当以上代码执行时，将产生以下输出。秒数在您的计算机上可能略有不同 -

. 
Finished in 0.002 seconds (files took 0.12101 seconds to load) 
1 example, 0 failures