t6302: use `main` as initial branch name

In 66713e84e7 (tests: prepare aligned mentions of the default branch
name, 2020-10-23), we started adjusting this test script for the default
initial branch name changing to `main`.

However, there is no need to wait for that: let's adjust the test script
to stop relying on a specific initial branch name by setting it
explicitly. This allows us to drop the `PREPARE_FOR_MAIN_BRANCH` prereq
from six test cases.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t6302-for-each-ref-filter.sh

@@ -7,6 +7,7 @@ test_description='test for-each-refs usage of ref-filter APIs'
 
 test_expect_success 'setup some history and refs' '
 	test_commit one &&
+	git branch -M main &&
 	test_commit two &&
 	test_commit three &&
 	git checkout -b side &&
@@ -26,17 +27,17 @@ test_expect_success 'setup some history and refs' '
 	git tag $sign -m "A signed tag" signed-tag &&
 	git tag $sign -m "Signed doubly" doubly-signed-tag signed-tag &&
 
-	git checkout master &&
-	git update-ref refs/odd/spot master
+	git checkout main &&
+	git update-ref refs/odd/spot main
 '
 
 test_expect_success 'filtering with --points-at' '
 	cat >expect <<-\EOF &&
-	refs/heads/master
+	refs/heads/main
 	refs/odd/spot
 	refs/tags/three
 	EOF
-	git for-each-ref --format="%(refname)" --points-at=master >actual &&
+	git for-each-ref --format="%(refname)" --points-at=main >actual &&
 	test_cmp expect actual
 '
 
@@ -53,13 +54,13 @@ test_expect_success 'check signed tags with --points-at' '
 
 test_expect_success 'filtering with --merged' '
 	cat >expect <<-\EOF &&
-	refs/heads/master
+	refs/heads/main
 	refs/odd/spot
 	refs/tags/one
 	refs/tags/three
 	refs/tags/two
 	EOF
-	git for-each-ref --format="%(refname)" --merged=master >actual &&
+	git for-each-ref --format="%(refname)" --merged=main >actual &&
 	test_cmp expect actual
 '
 
@@ -72,13 +73,13 @@ test_expect_success 'filtering with --no-merged' '
 	refs/tags/four
 	refs/tags/signed-tag
 	EOF
-	git for-each-ref --format="%(refname)" --no-merged=master >actual &&
+	git for-each-ref --format="%(refname)" --no-merged=main >actual &&
 	test_cmp expect actual
 '
 
 test_expect_success 'filtering with --contains' '
 	cat >expect <<-\EOF &&
-	refs/heads/master
+	refs/heads/main
 	refs/heads/side
 	refs/odd/spot
 	refs/tags/annotated-tag
@@ -113,7 +114,7 @@ test_expect_success '%(color) must fail' '
 	test_must_fail git for-each-ref --format="%(color)%(refname)"
 '
 
-test_expect_success PREPARE_FOR_MAIN_BRANCH 'left alignment is default' '
+test_expect_success 'left alignment is default' '
 	cat >expect <<-\EOF &&
 	refname is refs/heads/main    |refs/heads/main
 	refname is refs/heads/side    |refs/heads/side
@@ -131,7 +132,7 @@ test_expect_success PREPARE_FOR_MAIN_BRANCH 'left alignment is default' '
 	test_cmp expect actual
 '
 
-test_expect_success PREPARE_FOR_MAIN_BRANCH 'middle alignment' '
+test_expect_success 'middle alignment' '
 	cat >expect <<-\EOF &&
 	|  refname is refs/heads/main  |refs/heads/main
 	|  refname is refs/heads/side  |refs/heads/side
@@ -149,7 +150,7 @@ test_expect_success PREPARE_FOR_MAIN_BRANCH 'middle alignment' '
 	test_cmp expect actual
 '
 
-test_expect_success PREPARE_FOR_MAIN_BRANCH 'right alignment' '
+test_expect_success 'right alignment' '
 	cat >expect <<-\EOF &&
 	|    refname is refs/heads/main|refs/heads/main
 	|    refname is refs/heads/side|refs/heads/side
@@ -184,7 +185,7 @@ EOF
 test_align_permutations() {
 	while read -r option
 	do
-		test_expect_success PREPARE_FOR_MAIN_BRANCH "align:$option" '
+		test_expect_success "align:$option" '
 			git for-each-ref --format="|%(align:$option)refname is %(refname)%(end)|%(refname)" >actual &&
 			test_cmp expect actual
 		'
@@ -213,7 +214,7 @@ EOF
 
 # Individual atoms inside %(align:...) and %(end) must not be quoted.
 
-test_expect_success PREPARE_FOR_MAIN_BRANCH 'alignment with format quote' "
+test_expect_success 'alignment with format quote' "
 	cat >expect <<-\EOF &&
 	|'       '\''main| A U Thor'\''       '|
 	|'       '\''side| A U Thor'\''       '|
@@ -231,7 +232,7 @@ test_expect_success PREPARE_FOR_MAIN_BRANCH 'alignment with format quote' "
 	test_cmp expect actual
 "
 
-test_expect_success PREPARE_FOR_MAIN_BRANCH 'nested alignment with quote formatting' "
+test_expect_success 'nested alignment with quote formatting' "
 	cat >expect <<-\EOF &&
 	|'           main               '|
 	|'           side               '|
@@ -251,7 +252,7 @@ test_expect_success PREPARE_FOR_MAIN_BRANCH 'nested alignment with quote formatt
 
 test_expect_success 'check `%(contents:lines=1)`' '
 	cat >expect <<-\EOF &&
-	master |three
+	main |three
 	side |four
 	odd/spot |three
 	annotated-tag |An annotated tag
@@ -269,7 +270,7 @@ test_expect_success 'check `%(contents:lines=1)`' '
 
 test_expect_success 'check `%(contents:lines=0)`' '
 	cat >expect <<-\EOF &&
-	master |
+	main |
 	side |
 	odd/spot |
 	annotated-tag |
@@ -287,7 +288,7 @@ test_expect_success 'check `%(contents:lines=0)`' '
 
 test_expect_success 'check `%(contents:lines=99999)`' '
 	cat >expect <<-\EOF &&
-	master |three
+	main |three
 	side |four
 	odd/spot |three
 	annotated-tag |An annotated tag
@@ -360,7 +361,7 @@ test_expect_success 'improper usage of %(if), %(then), %(else) and %(end) atoms'
 test_expect_success 'check %(if)...%(then)...%(end) atoms' '
 	git for-each-ref --format="%(refname)%(if)%(authorname)%(then) Author: %(authorname)%(end)" >actual &&
 	cat >expect <<-\EOF &&
-	refs/heads/master Author: A U Thor
+	refs/heads/main Author: A U Thor
 	refs/heads/side Author: A U Thor
 	refs/odd/spot Author: A U Thor
 	refs/tags/annotated-tag
@@ -381,7 +382,7 @@ test_expect_success 'check %(if)...%(then)...%(end) atoms' '
 test_expect_success 'check %(if)...%(then)...%(else)...%(end) atoms' '
 	git for-each-ref --format="%(if)%(authorname)%(then)%(authorname)%(else)No author%(end): %(refname)" >actual &&
 	cat >expect <<-\EOF &&
-	A U Thor: refs/heads/master
+	A U Thor: refs/heads/main
 	A U Thor: refs/heads/side
 	A U Thor: refs/odd/spot
 	No author: refs/tags/annotated-tag
@@ -401,7 +402,7 @@ test_expect_success 'check %(if)...%(then)...%(else)...%(end) atoms' '
 test_expect_success 'ignore spaces in %(if) atom usage' '
 	git for-each-ref --format="%(refname:short): %(if)%(HEAD)%(then)Head ref%(else)Not Head ref%(end)" >actual &&
 	cat >expect <<-\EOF &&
-	master: Head ref
+	main: Head ref
 	side: Not Head ref
 	odd/spot: Not Head ref
 	annotated-tag: Not Head ref
@@ -420,19 +421,19 @@ test_expect_success 'ignore spaces in %(if) atom usage' '
 '
 
 test_expect_success 'check %(if:equals=<string>)' '
-	git for-each-ref --format="%(if:equals=master)%(refname:short)%(then)Found master%(else)Not master%(end)" refs/heads/ >actual &&
+	git for-each-ref --format="%(if:equals=main)%(refname:short)%(then)Found main%(else)Not main%(end)" refs/heads/ >actual &&
 	cat >expect <<-\EOF &&
-	Found master
-	Not master
+	Found main
+	Not main
 	EOF
 	test_cmp expect actual
 '
 
 test_expect_success 'check %(if:notequals=<string>)' '
-	git for-each-ref --format="%(if:notequals=master)%(refname:short)%(then)Not master%(else)Found master%(end)" refs/heads/ >actual &&
+	git for-each-ref --format="%(if:notequals=main)%(refname:short)%(then)Not main%(else)Found main%(end)" refs/heads/ >actual &&
 	cat >expect <<-\EOF &&
-	Found master
-	Not master
+	Found main
+	Not main
 	EOF
 	test_cmp expect actual
 '
@@ -443,11 +444,11 @@ test_expect_success '--merged is compatible with --no-merged' '
 
 test_expect_success 'validate worktree atom' '
 	cat >expect <<-EOF &&
-	master: $(pwd)
-	master_worktree: $(pwd)/worktree_dir
+	main: $(pwd)
+	main_worktree: $(pwd)/worktree_dir
 	side: not checked out
 	EOF
-	git worktree add -b master_worktree worktree_dir master &&
+	git worktree add -b main_worktree worktree_dir main &&
 	git for-each-ref --format="%(refname:short): %(if)%(worktreepath)%(then)%(worktreepath)%(else)not checked out%(end)" refs/heads/ >actual &&
 	rm -r worktree_dir &&
 	git worktree prune &&