2 files changed, 34 insertions, 0 deletions
diff --git a/t/t4013-diff-various.sh b/t/t4013-diff-various.sh
index 6cca8b84a6..87def81699 100755
--- a/t/t4013-diff-various.sh
+++ b/t/t4013-diff-various.sh
@@ -452,6 +452,37 @@ diff-tree --stat --compact-summary initial mode
 diff-tree -R --stat --compact-summary initial mode
 EOF
 
+test_expect_success 'log --diff-merges=on matches --diff-merges=separate' '
+	git log -p --diff-merges=separate master >result &&
+	process_diffs result >expected &&
+	git log -p --diff-merges=on master >result &&
+	process_diffs result >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'deny wrong log.diffMerges config' '
+	test_config log.diffMerges wrong-value &&
+	test_expect_code 128 git log
+'
+
+test_expect_success 'git config log.diffMerges first-parent' '
+	git log -p --diff-merges=first-parent master >result &&
+	process_diffs result >expected &&
+	test_config log.diffMerges first-parent &&
+	git log -p --diff-merges=on master >result &&
+	process_diffs result >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'git config log.diffMerges first-parent vs -m' '
+	git log -p --diff-merges=first-parent master >result &&
+	process_diffs result >expected &&
+	test_config log.diffMerges first-parent &&
+	git log -p -m master >result &&
+	process_diffs result >actual &&
+	test_cmp expected actual
+'
+
 test_expect_success 'log -S requires an argument' '
 	test_must_fail git log -S
 '
diff --git a/t/t9902-completion.sh b/t/t9902-completion.sh
index 04ce884ef5..4d732d6d4f 100755
--- a/t/t9902-completion.sh
+++ b/t/t9902-completion.sh
@@ -2306,6 +2306,7 @@ test_expect_success 'git config - variable name' '
 	test_completion "git config log.d" <<-\EOF
 	log.date Z
 	log.decorate Z
+	log.diffMerges Z
 	EOF
 '
 
@@ -2327,6 +2328,7 @@ test_expect_success 'git -c - variable name' '
 	test_completion "git -c log.d" <<-\EOF
 	log.date=Z
 	log.decorate=Z
+	log.diffMerges=Z
 	EOF
 '
 
@@ -2348,6 +2350,7 @@ test_expect_success 'git clone --config= - variable name' '
 	test_completion "git clone --config=log.d" <<-\EOF
 	log.date=Z
 	log.decorate=Z
+	log.diffMerges=Z
 	EOF
 '