apply: test rename A -> B -> C scenarios

Test that we can rename some file from B->C and then rename some other
file from A->B.  Do this with both exact rename patches (eg `rename from
...` / `rename to ...`) and patches that remove the files and replace
them entirely.

tests/apply/apply_helpers.h

@@ -133,6 +133,98 @@
 	" Take the hind shin of beef, cut off all the flesh off the leg-bone,\n" \
 	" which must be taken away entirely, or the soup will be greasy. Wash the\n"
 
+#define DIFF_RENAME_A_TO_B_TO_C \
+	"diff --git a/asparagus.txt b/asparagus.txt\n" \
+	"deleted file mode 100644\n" \
+	"index f516580..0000000\n" \
+	"--- a/asparagus.txt\n" \
+	"+++ /dev/null\n" \
+	"@@ -1,10 +0,0 @@\n" \
+	"-ASPARAGUS SOUP!\n" \
+	"-\n" \
+	"-Take four large bunches of asparagus, scrape it nicely, cut off one inch\n" \
+	"-of the tops, and lay them in water, chop the stalks and put them on the\n" \
+	"-fire with a piece of bacon, a large onion cut up, and pepper and salt;\n" \
+	"-add two quarts of water, boil them till the stalks are quite soft, then\n" \
+	"-pulp them through a sieve, and strain the water to it, which must be put\n" \
+	"-back in the pot; put into it a chicken cut up, with the tops of\n" \
+	"-asparagus which had been laid by, boil it until these last articles are\n" \
+	"-sufficiently done, thicken with flour, butter and milk, and serve it up.\n" \
+	"diff --git a/beef.txt b/beef.txt\n" \
+	"index 68f6182..f516580 100644\n" \
+	"--- a/beef.txt\n" \
+	"+++ b/beef.txt\n" \
+	"@@ -1,22 +1,10 @@\n" \
+	"-BEEF SOUP.\n" \
+	"+ASPARAGUS SOUP!\n" \
+	"\n" \
+	"-Take the hind shin of beef, cut off all the flesh off the leg-bone,\n" \
+	"-which must be taken away entirely, or the soup will be greasy. Wash the\n" \
+	"-meat clean and lay it in a pot, sprinkle over it one small\n" \
+	"-table-spoonful of pounded black pepper, and two of salt; three onions\n" \
+	"-the size of a hen's egg, cut small, six small carrots scraped and cut\n" \
+	"-up, two small turnips pared and cut into dice; pour on three quarts of\n" \
+	"-water, cover the pot close, and keep it gently and steadily boiling five\n" \
+	"-hours, which will leave about three pints of clear soup; do not let the\n" \
+	"-pot boil over, but take off the scum carefully, as it rises. When it has\n" \
+	"-boiled four hours, put in a small bundle of thyme and parsley, and a\n" \
+	"-pint of celery cut small, or a tea-spoonful of celery seed pounded.\n" \
+	"-These latter ingredients would lose their delicate flavour if boiled too\n" \
+	"-much. Just before you take it up, brown it in the following manner: put\n" \
+	"-a small table-spoonful of nice brown sugar into an iron skillet, set it\n" \
+	"-on the fire and stir it till it melts and looks very dark, pour into it\n" \
+	"-a ladle full of the soup, a little at a time; stirring it all the while.\n" \
+	"-Strain this browning and mix it well with the soup; take out the bundle\n" \
+	"-of thyme and parsley, put the nicest pieces of meat in your tureen, and\n" \
+	"-pour on the soup and vegetables; put in some toasted bread cut in dice,\n" \
+	"-and serve it up.\n" \
+	"+Take four large bunches of asparagus, scrape it nicely, cut off one inch\n" \
+	"+of the tops, and lay them in water, chop the stalks and put them on the\n" \
+	"+fire with a piece of bacon, a large onion cut up, and pepper and salt;\n" \
+	"+add two quarts of water, boil them till the stalks are quite soft, then\n" \
+	"+pulp them through a sieve, and strain the water to it, which must be put\n" \
+	"+back in the pot; put into it a chicken cut up, with the tops of\n" \
+	"+asparagus which had been laid by, boil it until these last articles are\n" \
+	"+sufficiently done, thicken with flour, butter and milk, and serve it up.\n" \
+	"diff --git a/notbeef.txt b/notbeef.txt\n" \
+	"new file mode 100644\n" \
+	"index 0000000..68f6182\n" \
+	"--- /dev/null\n" \
+	"+++ b/notbeef.txt\n" \
+	"@@ -0,0 +1,22 @@\n" \
+	"+BEEF SOUP.\n" \
+	"+\n" \
+	"+Take the hind shin of beef, cut off all the flesh off the leg-bone,\n" \
+	"+which must be taken away entirely, or the soup will be greasy. Wash the\n" \
+	"+meat clean and lay it in a pot, sprinkle over it one small\n" \
+	"+table-spoonful of pounded black pepper, and two of salt; three onions\n" \
+	"+the size of a hen's egg, cut small, six small carrots scraped and cut\n" \
+	"+up, two small turnips pared and cut into dice; pour on three quarts of\n" \
+	"+water, cover the pot close, and keep it gently and steadily boiling five\n" \
+	"+hours, which will leave about three pints of clear soup; do not let the\n" \
+	"+pot boil over, but take off the scum carefully, as it rises. When it has\n" \
+	"+boiled four hours, put in a small bundle of thyme and parsley, and a\n" \
+	"+pint of celery cut small, or a tea-spoonful of celery seed pounded.\n" \
+	"+These latter ingredients would lose their delicate flavour if boiled too\n" \
+	"+much. Just before you take it up, brown it in the following manner: put\n" \
+	"+a small table-spoonful of nice brown sugar into an iron skillet, set it\n" \
+	"+on the fire and stir it till it melts and looks very dark, pour into it\n" \
+	"+a ladle full of the soup, a little at a time; stirring it all the while.\n" \
+	"+Strain this browning and mix it well with the soup; take out the bundle\n" \
+	"+of thyme and parsley, put the nicest pieces of meat in your tureen, and\n" \
+	"+pour on the soup and vegetables; put in some toasted bread cut in dice,\n" \
+	"+and serve it up.\n"
+
+#define DIFF_RENAME_A_TO_B_TO_C_EXACT \
+	"diff --git a/asparagus.txt b/beef.txt\n" \
+	"similarity index 100%\n" \
+	"rename from asparagus.txt\n" \
+	"rename to beef.txt\n" \
+	"diff --git a/beef.txt b/notbeef.txt\n" \
+	"similarity index 100%\n" \
+	"rename from beef.txt\n" \
+	"rename to notbeef.txt\n"
+
 struct iterator_compare_data {
 	struct merge_index_entry *expected;
 	size_t cnt;

tests/apply/both.c

@@ -449,3 +449,53 @@ void test_apply_both__rename_and_modify(void)
 
 	git_diff_free(diff);
 }
+
+void test_apply_both__rename_a_to_b_to_c(void)
+{
+	git_diff *diff;
+
+	struct merge_index_entry both_expected[] = {
+		{ 0100644, "f51658077d85f2264fa179b4d0848268cb3475c3", 0, "beef.txt" },
+		{ 0100644, "4b7c5650008b2e747fe1809eeb5a1dde0e80850a", 0, "bouilli.txt" },
+		{ 0100644, "c4e6cca3ec6ae0148ed231f97257df8c311e015f", 0, "gravy.txt" },
+		{ 0100644, "68f6182f4c85d39e1309d97c7e456156dc9c0096", 0, "notbeef.txt" },
+		{ 0100644, "68af1fc7407fd9addf1701a87eb1c95c7494c598", 0, "oyster.txt" },
+		{ 0100644, "94d2c01087f48213bd157222d54edfefd77c9bba", 0, "veal.txt" },
+	};
+	size_t both_expected_cnt = sizeof(both_expected) /
+		sizeof(struct merge_index_entry);
+
+	cl_git_pass(git_diff_from_buffer(&diff, DIFF_RENAME_A_TO_B_TO_C,
+		strlen(DIFF_RENAME_A_TO_B_TO_C)));
+	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
+
+	validate_apply_index(repo, both_expected, both_expected_cnt);
+	validate_apply_workdir(repo, both_expected, both_expected_cnt);
+
+	git_diff_free(diff);
+}
+
+void test_apply_both__rename_a_to_b_to_c_exact(void)
+{
+	git_diff *diff;
+
+	struct merge_index_entry both_expected[] = {
+		{ 0100644, "f51658077d85f2264fa179b4d0848268cb3475c3", 0, "beef.txt" },
+		{ 0100644, "4b7c5650008b2e747fe1809eeb5a1dde0e80850a", 0, "bouilli.txt" },
+		{ 0100644, "c4e6cca3ec6ae0148ed231f97257df8c311e015f", 0, "gravy.txt" },
+		{ 0100644, "68f6182f4c85d39e1309d97c7e456156dc9c0096", 0, "notbeef.txt" },
+		{ 0100644, "68af1fc7407fd9addf1701a87eb1c95c7494c598", 0, "oyster.txt" },
+		{ 0100644, "94d2c01087f48213bd157222d54edfefd77c9bba", 0, "veal.txt" },
+	};
+	size_t both_expected_cnt = sizeof(both_expected) /
+		sizeof(struct merge_index_entry);
+
+	cl_git_pass(git_diff_from_buffer(&diff, DIFF_RENAME_A_TO_B_TO_C_EXACT,
+		strlen(DIFF_RENAME_A_TO_B_TO_C_EXACT)));
+	cl_git_pass(git_apply(repo, diff, GIT_APPLY_LOCATION_BOTH, NULL));
+
+	validate_apply_index(repo, both_expected, both_expected_cnt);
+	validate_apply_workdir(repo, both_expected, both_expected_cnt);
+
+	git_diff_free(diff);
+}