fix typos

Author: Xronophobe

chapter_27_hot_lava.asciidoc

@@ -22,7 +22,7 @@ and the end of our journey with this To-Do app and its tests.
 Let's recap our test structure so far:
 
 * We have a suite of "functional tests" that use Selenium to test that the whole app really works.
-  On several occations, the FTs have saved us from shipping broken code,
+  On several occasions, the FTs have saved us from shipping broken code,
   whether it was broken CSS, a broken database due to filesystem permissions, or broken email integration.
 
 * And we have a suit of "unit tests" that use Django's test client,
@@ -220,7 +220,7 @@ Anything longer than a few seconds and you're going to let your attention wander
 you context-switch, and the flow state is gone.
 And the flow state is a fragile dream.
 Once it's gone, it takes a long time to come back.footnote:[
-Some people says it takes at least 15 minutes to get back into the flow state.
+Some people say it takes at least 15 minutes to get back into the flow state.
 In my experience, that's overblown,
 and I sometimes wonder if it's thanks to TDD.
 I think TDD reduces the cognitive load of programming.
@@ -274,7 +274,7 @@ Functional/End-to-end tests::
 
 
 Integration tests::
-    The purpose of an integration tests should be to checks that the code
+    The purpose of integration tests should be to check that the code
     you write is integrated correctly with some "external" system or dependency.
 
 
@@ -561,7 +561,7 @@ What that's meant is that some of the more advanced uses of TDD,
 particularly the interplay between testing and architecture,
 have been beyond the scope of this book.
 
-But I hope that this chapter has been a bit a guide to find your way
+But I hope that this chapter has been a bit of a guide to find your way
 around that topic as your career progresses.