--- a/modules/stdlib/spec/functions/is_float_spec.rb	Tue Dec 31 13:49:38 2019 +0000
+++ b/modules/stdlib/spec/functions/is_float_spec.rb	Fri Jan 03 19:56:04 2020 +0000
@@ -1,33 +1,40 @@
-#! /usr/bin/env ruby -S rspec
 require 'spec_helper'
 
-describe "the is_float function" do
-  let(:scope) { PuppetlabsSpec::PuppetInternals.scope }
+describe 'is_float' do
+  it { is_expected.not_to eq(nil) }
+
+  it { is_expected.to run.with_params.and_raise_error(Puppet::ParseError, %r{wrong number of arguments}i) }
+  it { is_expected.to run.with_params(0.1, 0.2).and_raise_error(Puppet::ParseError, %r{wrong number of arguments}i) }
 
-  it "should exist" do
-    expect(Puppet::Parser::Functions.function("is_float")).to eq("function_is_float")
-  end
-
-  it "should raise a ParseError if there is less than 1 arguments" do
-    expect { scope.function_is_float([]) }.to( raise_error(Puppet::ParseError))
+  describe 'passing a string' do
+    it { is_expected.to run.with_params('0.1').and_return(true) }
+    it { is_expected.to run.with_params('1.0').and_return(true) }
+    it { is_expected.to run.with_params('1').and_return(false) }
+    it { is_expected.to run.with_params('one').and_return(false) }
+    it { is_expected.to run.with_params('one 1.0').and_return(false) }
+    it { is_expected.to run.with_params('1.0 one').and_return(false) }
   end
 
-  it "should return true if a float" do
-    result = scope.function_is_float(["0.12"])
-    expect(result).to(eq(true))
-  end
-
-  it "should return false if a string" do
-    result = scope.function_is_float(["asdf"])
-    expect(result).to(eq(false))
+  describe 'passing numbers' do
+    it { is_expected.to run.with_params(0.1).and_return(true) }
+    it { is_expected.to run.with_params(1.0).and_return(true) }
+    it { is_expected.to run.with_params(1).and_return(false) }
   end
 
-  it "should return false if an integer" do
-    result = scope.function_is_float(["3"])
-    expect(result).to(eq(false))
-  end
-  it "should return true if a float is created from an arithmetical operation" do
-    result = scope.function_is_float([3.2*2])
-    expect(result).to(eq(true))
+  context 'with deprecation warning' do
+    after(:each) do
+      ENV.delete('STDLIB_LOG_DEPRECATIONS')
+    end
+    # Checking for deprecation warning, which should only be provoked when the env variable for it is set.
+    it 'displays a single deprecation' do
+      ENV['STDLIB_LOG_DEPRECATIONS'] = 'true'
+      scope.expects(:warning).with(includes('This method is deprecated'))
+      is_expected.to run.with_params(2.2).and_return(true)
+    end
+    it 'displays no warning for deprecation' do
+      ENV['STDLIB_LOG_DEPRECATIONS'] = 'false'
+      scope.expects(:warning).with(includes('This method is deprecated')).never
+      is_expected.to run.with_params(1.0).and_return(true)
+    end
   end
 end