Do not mistreat empty arguments to font alternating macros

as vertical spacing requests.  Bug found with xmahjongg(6).

3 files changed, 30 insertions, 2 deletions

diff --git a/regress/usr.bin/mandoc/man/BI/Makefile b/regress/usr.bin/mandoc/man/BI/Makefile
index c8a65412887..b23aeeadb65 100644
--- a/regress/usr.bin/mandoc/man/BI/Makefile
+++ b/regress/usr.bin/mandoc/man/BI/Makefile
@@ -1,5 +1,5 @@
-# $OpenBSD: Makefile,v 1.2 2011/11/17 16:28:45 schwarze Exp $
+# $OpenBSD: Makefile,v 1.3 2015/04/06 22:06:06 schwarze Exp $
 
-REGRESS_TARGETS=literal
+REGRESS_TARGETS	 = emptyargs literal
 
 .include <bsd.regress.mk>
diff --git a/regress/usr.bin/mandoc/man/BI/emptyargs.in b/regress/usr.bin/mandoc/man/BI/emptyargs.in
new file mode 100644
index 00000000000..acbf4986541
--- /dev/null
+++ b/regress/usr.bin/mandoc/man/BI/emptyargs.in
@@ -0,0 +1,10 @@
+.TH BI-EMPTYARGS 1 "April 6, 2015" OpenBSD
+.SH NAME
+BI-emptyargs \- empty arguments to font alternation macros
+.SH DESCRIPTION
+leading text
+.TP 6n
+.BI bold italic "" ""
+.BI bold "" "" italic 
+.PP
+trailing text
diff --git a/regress/usr.bin/mandoc/man/BI/emptyargs.out_ascii b/regress/usr.bin/mandoc/man/BI/emptyargs.out_ascii
new file mode 100644
index 00000000000..3469b7e0c1a
--- /dev/null
+++ b/regress/usr.bin/mandoc/man/BI/emptyargs.out_ascii
@@ -0,0 +1,18 @@
+BI-EMPTYARGS(1)             General Commands Manual            BI-EMPTYARGS(1)
+
+
+
+NNAAMMEE
+       BI-emptyargs - empty arguments to font alternation macros
+
+DDEESSCCRRIIPPTTIIOONN
+       leading text
+
+       bboolldd_i_t_a_l_i_c
+             bboolldd_i_t_a_l_i_c
+
+       trailing text
+
+
+
+OpenBSD                          April 6, 2015                 BI-EMPTYARGS(1)