Add grammar fixes, add tdd section, add mini test example

Author: schaui6

sites/en/testing/testing_frameworks.step

@@ -64,7 +64,7 @@ bundle exec rspec spec/controllers/post_controller_spec.rb
 ## RSpec Basics
 
 <div class="console"><pre>
-1 RSpec.describe Tree do
+1 describe Tree do
 2  it "is able to age by 1 year increments" do
 3    orange_tree = Tree.new
 4    orange_tree.age   
@@ -91,6 +91,46 @@ Remember in our example on line 5? 'to eq' is a matcher. RSpec has many built-in
 Check out the other built-in matchers!
 https://www.relishapp.com/rspec/rspec-expectations/docs/built-in-matchers
 
+# Mini Test
+In case you were curious to see how tests are written in Mini Test.  Although Mini Test allows you in 'expectation style' which is very similar to how RSpec tests are written. 
+
+<div class="console">
+<pre>
+class TestTree < Minitest::Test
+
+  def setup
+    @orange_tree = Tree.new
+    @orange_tree.age
+  end
+
+  def test_age_by_one_year_increments
+    assert_equal 1, @orange_tree.age
+  end
+end
+</pre>
+</div>
+
+To run the test enter the following in Terminal/Command Prompt:
+
+<div class="console">
+<pre>
+ruby tree_test.rb
+</pre>
+</div>
+
+Once you run the test this is how the test looks like:
+<div class="console">
+<pre>
+$ ruby tree_test.rb
+Run options: --seed 30102
+
+#Running:
+
+.
+Finished in 0.000980s, 1020.4082 runs/s, 1020.4082 assertions/s.
+1 runs, 1 assertions, 0 failures, 0 errors, 0 skips
+</pre>
+</div>
 
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sites/en/testing/what_are_tests.step

@@ -15,7 +15,10 @@ How do we determine if an orange is ripe? Well, we can have oranges age and if i
 You could think of tests as a requirement list.  Every time a change is made we want to test to see if our code still meets those requirements. For example, as our program becomes increasingly complex and we want to have our tree to have a certain lifespan, would it make sense for our tree to continue to create oranges after exceeding that lifespan?   
 
 # Why Is It Important That We Test?
-For situations like our tree's lifespan is a prime example of why tests are important.  As our program become more complex over time the tests tells us that a basic requirement is not fulfilled and needs to be addressed.  Can you imagine looking at pages and pages of code that was written by someone else or many years ago without a way to trace exactly where the bug is?  Tests can help!
+For situations like our tree's lifespan is a prime example of why tests are important.  As our program becomes more complex over time the tests tells us that a basic requirement is not fulfilled and needs to be addressed.  Can you imagine looking at pages and pages of code that was written by someone else or many years ago without a way to trace exactly where the bug is?  Tests can help!
+
+# Test Driven Development
+Test-driven development (TDD) is a development technique where you must first write a test that fails before you write new functional code. TDD is a great way to develop your program! Add a test, run all tests, write code, run tests, and then refactor code!
 
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