diff --git a/c/reg_test/expected/out b/c/reg_test/expected/out
index ddd5068d1..8c2d9c581 100644
--- a/c/reg_test/expected/out
+++ b/c/reg_test/expected/out
@@ -1530,6 +1530,53 @@ mlr filter -v $x =~ "^a.*"."d$" ./reg_test/input/regex.dkvp
         d$ (literal).
 x=abcd,y=ghi
 
+mlr filter -v $x =~ "bcd"i ./reg_test/input/regex.dkvp
+=~ (operator):
+    x (field_name).
+    bcd (regexi).
+x=abcd,y=ghi
+x=ABCD,y=GHI
+x=abcde,y=ghi
+x=ABCDE,y=GHI
+
+mlr filter -v $x =~ "^bcd"i ./reg_test/input/regex.dkvp
+=~ (operator):
+    x (field_name).
+    ^bcd (regexi).
+
+mlr filter -v $x =~ "^abc"i ./reg_test/input/regex.dkvp
+=~ (operator):
+    x (field_name).
+    ^abc (regexi).
+x=abc,y=def
+x=ABC,y=DEF
+x=abcd,y=ghi
+x=ABCD,y=GHI
+x=abcde,y=ghi
+x=ABCDE,y=GHI
+
+mlr filter -v $x =~ "^abc$"i ./reg_test/input/regex.dkvp
+=~ (operator):
+    x (field_name).
+    ^abc$ (regexi).
+x=abc,y=def
+x=ABC,y=DEF
+
+mlr filter -v $x =~ "^a.*d$"i ./reg_test/input/regex.dkvp
+=~ (operator):
+    x (field_name).
+    ^a.*d$ (regexi).
+x=abcd,y=ghi
+x=ABCD,y=GHI
+
+mlr filter -v $x =~ "^a.*"."d$"i ./reg_test/input/regex.dkvp
+=~ (operator):
+    x (field_name).
+    . (operator):
+        ^a.* (literal).
+        d$ (regexi).
+x=abcd,y=ghi
+
 mlr --csvlite put $gmt=sec2gmt($sec) ./reg_test/input/sec2gmt
 sec,gmt
 0,1970-01-01T00:00:00Z
diff --git a/c/reg_test/input/regex.dkvp b/c/reg_test/input/regex.dkvp
index 2dab66388..8ade6d8d3 100644
--- a/c/reg_test/input/regex.dkvp
+++ b/c/reg_test/input/regex.dkvp
@@ -1,3 +1,6 @@
 x=abc,y=def
+x=ABC,y=DEF
 x=abcd,y=ghi
+x=ABCD,y=GHI
 x=abcde,y=ghi
+x=ABCDE,y=GHI
diff --git a/c/reg_test/run b/c/reg_test/run
index 91830d549..fc7f1d4f0 100755
--- a/c/reg_test/run
+++ b/c/reg_test/run
@@ -315,6 +315,13 @@ run_mlr filter -v '$x =~ "^abc$"'     $indir/regex.dkvp
 run_mlr filter -v '$x =~ "^a.*d$"'    $indir/regex.dkvp
 run_mlr filter -v '$x =~ "^a.*"."d$"' $indir/regex.dkvp
 
+run_mlr filter -v '$x =~ "bcd"i'       $indir/regex.dkvp
+run_mlr filter -v '$x =~ "^bcd"i'      $indir/regex.dkvp
+run_mlr filter -v '$x =~ "^abc"i'      $indir/regex.dkvp
+run_mlr filter -v '$x =~ "^abc$"i'     $indir/regex.dkvp
+run_mlr filter -v '$x =~ "^a.*d$"i'    $indir/regex.dkvp
+run_mlr filter -v '$x =~ "^a.*"."d$"i' $indir/regex.dkvp
+
 run_mlr --csvlite put '$gmt=sec2gmt($sec)' $indir/sec2gmt
 run_mlr --csvlite put '$sec=gmt2sec($gmt)' $indir/gmt2sec