Update chapter_20_mocking_1.asciidoc #1292

Job	Run time
chapter-tests (test_chapter_01)	2m 38s
chapter-tests (test_chapter_02_unittest)	2m 34s
chapter-tests (test_chapter_03_unit_test_first_view)	2m 55s
chapter-tests (test_chapter_04_philosophy_and_refactoring)	3m 57s
chapter-tests (test_chapter_05_post_and_database)	3m 57s
chapter-tests (test_chapter_06_explicit_waits_1)	4m 12s
chapter-tests (test_chapter_07_working_incrementally)	6m 3s
chapter-tests (test_chapter_08_prettification)	5m 13s
chapter-tests (test_chapter_09_docker)	4m 19s
chapter-tests (test_chapter_10_production_readiness)	5m 10s
chapter-tests (test_chapter_11_server_prep)	3m 10s
chapter-tests (test_chapter_12_ansible)	2m 35s
chapter-tests (test_chapter_13_organising_test_files)	3m 42s
chapter-tests (test_chapter_14_database_layer_validation)	5m 56s
chapter-tests (test_chapter_15_simple_form)	5m 8s
chapter-tests (test_chapter_16_advanced_forms)	6m 17s
chapter-tests (test_chapter_17_javascript)	3m 45s
chapter-tests (test_chapter_19_spiking_custom_auth)	4m 29s
chapter-tests (test_chapter_20_mocking_1)	3m 42s
chapter-tests (test_chapter_21_mocking_2)	3m 56s
chapter-tests (test_chapter_22_fixtures_and_wait_decorator)	3m 37s
chapter-tests (test_chapter_23_debugging_prod)	2m 59s
chapter-tests (test_chapter_24_outside_in)	5m 37s
chapter-tests (test_chapter_25_CI)	3m 14s
chapter-tests (test_chapter_26_page_pattern)	2m 58s
	1h 42m 3s

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