diff --git a/test/couch_log_trunc_io_fmt_test.erl b/test/couch_log_trunc_io_fmt_test.erl
index 13d74d2..77d5554 100644
--- a/test/couch_log_trunc_io_fmt_test.erl
+++ b/test/couch_log_trunc_io_fmt_test.erl
@@ -28,32 +28,58 @@
     end, cases()).
 
 
+
+chomp_test() ->
+    R1 = couch_log_trunc_io_fmt:format("\n", [], 1024, [{chomp, true}]),
+    ?assertEqual("", lists:flatten(R1)),
+    R2 = couch_log_trunc_io_fmt:format("~n", [], 1024, [{chomp, true}]),
+    ?assertEqual("", lists:flatten(R2)).
+
+
 cases() ->
     [
         {"", [], ""},
+        {"stuff\n\t", [], "stuff\n\t"},
         {"~w", [foo], "foo"},
         {"~p", [bar], "bar"},
         {"~W", [{{{2}}}, 2], "{{...}}"},
         {"~P", [{{{ohai}}}, 1], "{...}"},
         {"~s", [[$s, [$t, [$u, [$f, [$f]]]]]], "stuff"},
+        {"~4s", ["stuff"], "stuf"},
+        {"~8s", ["stuff"], "   stuff"},
+        {"~.8s", ["stuff"], "stuff   "},
+        {"~10.4s", ["stuff"], "      stuf"},
+        {"~10.6s", ["stuff"], "    stuff "},
+        {"~10.5s", ["stuff"], "     stuff"},
+        {"~10.10s", ["stuff"], "     stuff"},
         {"~r", [{reason, [{x, k, [c, d]}]}], "reason at x:k/2"},
         {"~e", [1.0], "1.00000e+0"},
         {"~f", [1.0], "1.000000"},
+        {"~f", [0.000323], "0.000323"},
+        {"~f", [31.4], "31.400000"},
+        {"~f", [-2.3], "-2.300000"},
         {"~g", [1.0], "1.00000"},
+        {"~b", [-15], "-15"},
         {"~b", [15], "15"},
         {"~B", [15], "15"},
         {"~.16b", [15], "f"},
         {"~.16B", [15], "F"},
+        {"~.16b", [-15], "-f"},
+        {"~.16B", [-15], "-F"},
         {"~.16x", [15, "16#"], "16#f"},
         {"~.16x", [15, '16#'], "16#f"},
+        {"~.16x", [-15, "16#"], "-16#f"},
         {"~.16X", [15, "16#"], "16#F"},
         {"~.16X", [15, '16#'], "16#F"},
+        {"~.16X", [-15, "16#"], "-16#F"},
         {"~.16#", [15], "16#F"},
         {"~.16+", [15], "16#f"},
         {"~c", [$z], "z"},
         {"~tc", [$g], "g"},
         {"~~", [], "\~"},
         {"~n", [], "\n"},
+        {"~2n", [], "\n\n"},
+        {"~3n", [], "\n\n\n"},
         {"~i", [ignored], ""},
         {"~2.w", [1], " 1"},
         {"~*w", [2, 1], " 1"},