Add testsuite

* Makefile: Build the testsuite.
Support make install and make check.
* xenv.l: Emit synclines in ECHO.
Preprocessor statements are removed completely, together with
the trailing newline.
* t/comment.at: New file.
* t/ifdef.at: New file.
* t/ifndef.at: New file.
* t/ifnset.at: New file.
* t/ifset.at: New file.
* t/quote.at: New file.
* t/set.at: New file.
* t/testsuite.at: New file.
* t/unset.at: New file.

21 files changed, 1114 insertions, 29 deletions

diff --git a/.gitignore b/.gitignore
index 957ecb4..1cb3463 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,8 +1,13 @@
+.gdbinit
 xenv
 lex.yy.c
 tmp
 .emacs*
 *~
 \#*#
-*.tar
+*.tar.gz
 core
+testsuite
+testsuite.dir
+testsuite.log
+package.m4
diff --git a/Makefile b/Makefile
index 3527d33..db0dd05 100644
--- a/Makefile
+++ b/Makefile
@@ -1,9 +1,41 @@
+# This file is part of xenv
+# Copyright (C) 2021 Sergey Poznyakoff
+#
+# Xenv is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# Xenv is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with xenv. If not, see <http://www.gnu.org/licenses/>. */
+
 CPPFLAGS =
 CFLAGS = -ggdb -Wall
 LEXFLAGS = -F
 
-PACKAGE = xenv
-VERSION = 0.1
+# Installation prefix
+PREFIX  = /usr/local
+MANDIR  = $(PREFIX)/share/man
+BINDIR  = $(PREFIX)/bin
+MAN1DIR = $(MANDIR)/man1
+
+# Install program.  Use cp(1) if not available.
+INSTALL = install
+# Program to make a directory hierarchy.
+MKHIER  = install -d
+
+# #############################
+# Building the program.
+# #############################
+PACKAGE_NAME = xenv
+PACKAGE_VERSION = 0.1
+PACKAGE_TARNAME = $(PACKAGE_NAME)-$(PACKAGE_VERSION)
+PACKAGE_BUGREPORT = gray@gnu.org
 
 xenv: lex.yy.c
 	$(CC) -oxenv $(CPPFLAGS) $(CFLAGS) lex.yy.c
@@ -11,12 +43,91 @@ lex.yy.c: xenv.l
 	flex $(LEXFLAGS) xenv.l
 clean:
 	rm -f xenv lex.yy.c
-DISTNAME = $(PACKAGE)-$(VERSION)
-DISTDIR = $(DISTNAME)
+
+check: xenv testsuite
+	@./testsuite
+
+# ###############################
+# Building the testsuite.
+# ###############################
+AUTOM4TE = autom4te
+AUTOTEST = $(AUTOM4TE) --language=autotest
+
+TESTSUITE_AT = \
+ t/testsuite.at \
+ t/asndfl.at\
+ t/braces.at\
+ t/comment.at\
+ t/errmsg.at\
+ t/error.at\
+ t/ifdef.at\
+ t/ifndef.at\
+ t/ifnset.at\
+ t/ifset.at\
+ t/quote.at\
+ t/set.at\
+ t/simple.at\
+ t/ternary.at\
+ t/unset.at\
+ t/usealt.at\
+ t/usedfl.at
+
+package.m4: Makefile
+	{                                      \
+	  echo '# Signature of the current package.'; \
+	  echo 'm4_define([AT_PACKAGE_NAME],      [$(PACKAGE_NAME)])'; \
+	  echo 'm4_define([AT_PACKAGE_TARNAME],   [$(PACKAGE_TARNAME)])'; \
+	  echo 'm4_define([AT_PACKAGE_VERSION],   [$(PACKAGE_VERSION)])'; \
+	  echo 'm4_define([AT_PACKAGE_STRING],    [$(PACKAGE_TARNAME)])'; \
+	  echo 'm4_define([AT_PACKAGE_BUGREPORT], [$(PACKAGE_BUGREPORT)])'; \
+	} > package.m4
+
+EXTRA_DIST = atlocal package.m4
+
+testsuite: package.m4 $(TESTSUITE_AT)
+	$(AUTOTEST) -I . -I t t/testsuite.at -o testsuite
+
+# ###############################
+# Install
+# ###############################
+
+install: install-bin install-man
+
+install-bin: xenv
+	$(MKHIER) $(DESTDIR)$(BINDIR)
+	$(INSTALL) xenv $(DESTDIR)$(BINDIR)
+
+install-man:
+	$(MKHIER) $(DESTDIR)$(MAN1DIR)
+	$(INSTALL) xenv.1 $(DESTDIR)$(MAN1DIR)
+
+# ###############################
+# Distribution
+# ###############################
+DISTDIR = $(PACKAGE_TARNAME)
+DISTFILES = xenv.l xenv.1 Makefile lex.yy.c testsuite
+
 distdir: lex.yy.c
 	rm -rf $(DISTDIR)
 	mkdir $(DISTDIR)
-	cp xenv.l xenv.1 Makefile lex.yy.c $(DISTDIR)
+	cp $(DISTFILES) $(EXTRA_DIST) $(DISTDIR)
+	mkdir $(DISTDIR)/t
+	cp $(TESTSUITE_AT) $(DISTDIR)/t
+
 dist: distdir
-	tar cf $(DISTNAME).tar $(DISTDIR)
+	tar zcf $(PACKAGE_TARNAME).tar.gz $(DISTDIR)
 	rm -rf $(DISTDIR)
+
+
+distcheck: dist
+	tar xfz $(PACKAGE_TARNAME).tar.gz
+	if $(MAKE) -C $(DISTDIR) $(DISTCHECKFLAGS) check; then \
+          text="$(DISTDIR).tar.gz ready for distribution"; \
+	  echo "$$text" | sed s/./=/g; \
+	  echo "$$text"; \
+	  echo "$$text" | sed s/./=/g; \
+          rm -rf $(DISTDIR); \
+        else \
+          exit 2; \
+        fi
+
diff --git a/atlocal b/atlocal
new file mode 100644
index 0000000..32e826b
--- /dev/null
+++ b/atlocal
@@ -0,0 +1 @@
+PATH=.:$PATH
\ No newline at end of file
diff --git a/t/asndfl.at b/t/asndfl.at
new file mode 100644
index 0000000..0b8baa9
--- /dev/null
+++ b/t/asndfl.at
@@ -0,0 +1,69 @@
+# This file is part of xenv                         -*- autotest -*-
+# Copyright (C) 2021 Sergey Poznyakoff
+#
+# Xenv is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# Xenv is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with xenv. If not, see <http://www.gnu.org/licenses/>. */
+
+AT_SETUP([Assign default values])
+
+AT_DATA([input],
+[Lorem ipsum ${OBJ=dolor} sit am${EX:=et}, consectetur adipiscing elit,
+sed do eiusmod tempor incididunt ut labore $EX ${OBJ}e magna aliqua.
+])
+
+AT_CHECK([ 
+unset OBJ EX
+xenv input
+],
+[0],
+[Lorem ipsum dolor sit amet, consectetur adipiscing elit,
+sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+])
+
+AT_CHECK([
+OBJ=nitor
+export OBJ
+unset EX
+xenv input
+],
+[0],
+[Lorem ipsum nitor sit amet, consectetur adipiscing elit,
+sed do eiusmod tempor incididunt ut labore et nitore magna aliqua.
+])
+
+AT_CHECK([
+OBJ=nitor
+export OBJ
+EX=abunt
+export EX
+xenv input
+],
+[0],
+[Lorem ipsum nitor sit amabunt, consectetur adipiscing elit,
+sed do eiusmod tempor incididunt ut labore abunt nitore magna aliqua.
+])
+
+AT_CHECK([
+OBJ=
+export OBJ
+EX=
+export EX
+xenv input
+],
+[0],
+[Lorem ipsum  sit amet, consectetur adipiscing elit,
+sed do eiusmod tempor incididunt ut labore et e magna aliqua.
+])
+
+
+AT_CLEANUP
diff --git a/t/braces.at b/t/braces.at
new file mode 100644
index 0000000..58de00a
--- /dev/null
+++ b/t/braces.at
@@ -0,0 +1,54 @@
+# This file is part of xenv                         -*- autotest -*-
+# Copyright (C) 2021 Sergey Poznyakoff
+#
+# Xenv is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# Xenv is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with xenv. If not, see <http://www.gnu.org/licenses/>. */
+
+AT_SETUP([Brace expansion])
+AT_DATA([input],
+[foo is ${X_FOO}, bar is ${X_BAR}.
+])
+AT_CHECK([
+unset X_FOO
+unset X_BAR
+xenv input],
+[0],
+[foo is , bar is .
+])
+AT_CHECK([
+unset X_FOO
+unset X_BAR
+xenv -u input],
+[65],
+[foo is , bar is .
+],
+[input:1: variable X_FOO not defined
+input:1: variable X_BAR not defined
+])
+AT_CHECK([
+unset X_FOO
+unset X_BAR
+xenv -ur input],
+[65],
+[foo is ${X_FOO}, bar is ${X_BAR}.
+],
+[input:1: variable X_FOO not defined
+input:1: variable X_BAR not defined
+])
+AT_CHECK([
+X_FOO=baz X_BAR=qux xenv -u input],
+[0],
+[foo is baz, bar is qux.
+])
+
+AT_CLEANUP
\ No newline at end of file
diff --git a/t/comment.at b/t/comment.at
new file mode 100644
index 0000000..b92f7f1
--- /dev/null
+++ b/t/comment.at
@@ -0,0 +1,39 @@
+# This file is part of xenv                         -*- autotest -*-
+# Copyright (C) 2021 Sergey Poznyakoff
+#
+# Xenv is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# Xenv is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with xenv. If not, see <http://www.gnu.org/licenses/>. */
+
+AT_SETUP([Comments])
+AT_DATA([input],
+[${* Comment statements are ignored *}
+Lorem ipsum dolor sit amet, consectetur adipiscing elit,
+${* Comments can be multi-line,
+as shown here.  Variable references in comments (${X:?}) are ignored.
+Newline character following the comment is retained. *}
+sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris
+nisi ut aliquip ex ea commodo consequat.
+])
+AT_CHECK([unset X
+xenv input
+],
+[0],
+[
+Lorem ipsum dolor sit amet, consectetur adipiscing elit,
+
+sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris
+nisi ut aliquip ex ea commodo consequat.
+])
+AT_CLEANUP
diff --git a/t/errmsg.at b/t/errmsg.at
new file mode 100644
index 0000000..15ff22f
--- /dev/null
+++ b/t/errmsg.at
@@ -0,0 +1,86 @@
+# This file is part of xenv                         -*- autotest -*-
+# Copyright (C) 2021 Sergey Poznyakoff
+#
+# Xenv is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# Xenv is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with xenv. If not, see <http://www.gnu.org/licenses/>. */
+
+AT_SETUP([Display Custom Error if Null or Unset])
+
+AT_DATA([input],
+[Ut enim ad minim ${V1?Should have set V1}, quis nostrud exercitation ullamco
+${V2:?Should have set V2 to a non-empty value} nisi ut aliquip ex ea commodo consequat.
+])
+
+AT_CHECK([
+V1=veniam
+V2=laboris
+export V1 V2
+xenv input
+],
+[0],
+[Ut enim ad minim veniam, quis nostrud exercitation ullamco
+laboris nisi ut aliquip ex ea commodo consequat.
+])
+
+AT_CHECK([
+V1=
+V2=laboris
+export V1 V2
+xenv input
+],
+[0],
+[Ut enim ad minim , quis nostrud exercitation ullamco
+laboris nisi ut aliquip ex ea commodo consequat.
+])
+
+AT_CHECK([
+unset V1
+V2=laboris
+export V2
+xenv input
+],
+[0],
+[Ut enim ad minim , quis nostrud exercitation ullamco
+laboris nisi ut aliquip ex ea commodo consequat.
+],
+[input:1: Should have set V1
+])
+
+AT_CHECK([
+unset V1 V2
+xenv input
+],
+[0],
+[Ut enim ad minim , quis nostrud exercitation ullamco
+ nisi ut aliquip ex ea commodo consequat.
+],
+[input:1: Should have set V1
+input:2: Should have set V2 to a non-empty value
+])
+
+AT_CHECK([
+unset V1
+V2=
+export V2
+xenv input
+],
+[0],
+[Ut enim ad minim , quis nostrud exercitation ullamco
+ nisi ut aliquip ex ea commodo consequat.
+],
+[input:1: Should have set V1
+input:2: Should have set V2 to a non-empty value
+])
+
+AT_CLEANUP
+
diff --git a/t/error.at b/t/error.at
new file mode 100644
index 0000000..378d76b
--- /dev/null
+++ b/t/error.at
@@ -0,0 +1,86 @@
+# This file is part of xenv                         -*- autotest -*-
+# Copyright (C) 2021 Sergey Poznyakoff
+#
+# Xenv is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# Xenv is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with xenv. If not, see <http://www.gnu.org/licenses/>. */
+
+AT_SETUP([Display Error if Null or Unset])
+
+AT_DATA([input],
+[Ut enim ad minim ${V1?}, quis nostrud exercitation ullamco
+${V2:?} nisi ut aliquip ex ea commodo consequat.
+])
+
+AT_CHECK([
+V1=veniam
+V2=laboris
+export V1 V2
+xenv input
+],
+[0],
+[Ut enim ad minim veniam, quis nostrud exercitation ullamco
+laboris nisi ut aliquip ex ea commodo consequat.
+])
+
+AT_CHECK([
+V1=
+V2=laboris
+export V1 V2
+xenv input
+],
+[0],
+[Ut enim ad minim , quis nostrud exercitation ullamco
+laboris nisi ut aliquip ex ea commodo consequat.
+])
+
+AT_CHECK([
+unset V1
+V2=laboris
+export V2
+xenv input
+],
+[0],
+[Ut enim ad minim , quis nostrud exercitation ullamco
+laboris nisi ut aliquip ex ea commodo consequat.
+],
+[input:1: variable V1 not set
+])
+
+AT_CHECK([
+unset V1 V2
+xenv input
+],
+[0],
+[Ut enim ad minim , quis nostrud exercitation ullamco
+ nisi ut aliquip ex ea commodo consequat.
+],
+[input:1: variable V1 not set
+input:2: variable V2 null or not set
+])
+
+AT_CHECK([
+unset V1
+V2=
+export V2
+xenv input
+],
+[0],
+[Ut enim ad minim , quis nostrud exercitation ullamco
+ nisi ut aliquip ex ea commodo consequat.
+],
+[input:1: variable V1 not set
+input:2: variable V2 null or not set
+])
+
+AT_CLEANUP
+
diff --git a/t/ifdef.at b/t/ifdef.at
new file mode 100644
index 0000000..97dd888
--- /dev/null
+++ b/t/ifdef.at
@@ -0,0 +1,60 @@
+# This file is part of xenv                         -*- autotest -*-
+# Copyright (C) 2021 Sergey Poznyakoff
+#
+# Xenv is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# Xenv is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with xenv. If not, see <http://www.gnu.org/licenses/>. */
+
+AT_SETUP([$$ifdef])
+AT_DATA([input],
+[Duis aute irure dolor in reprehenderit in voluptate velit esse
+$$ifdef X
+cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat
+$$else
+$$ ifdef Y
+...
+$$ endif
+$$ endif
+cupidatat non proident, sunt in culpa qui officia deserunt mollit
+anim id est laborum.
+])
+
+AT_CHECK([unset X Y
+xenv input
+],
+[0],
+[Duis aute irure dolor in reprehenderit in voluptate velit esse
+cupidatat non proident, sunt in culpa qui officia deserunt mollit
+anim id est laborum.
+])
+
+AT_CHECK([unset X
+Y= xenv input
+],
+[0],
+[Duis aute irure dolor in reprehenderit in voluptate velit esse
+...
+cupidatat non proident, sunt in culpa qui officia deserunt mollit
+anim id est laborum.
+])
+
+AT_CHECK([
+X= xenv input
+],
+[0],
+[Duis aute irure dolor in reprehenderit in voluptate velit esse
+cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat
+cupidatat non proident, sunt in culpa qui officia deserunt mollit
+anim id est laborum.
+])
+
+AT_CLEANUP
diff --git a/t/ifndef.at b/t/ifndef.at
new file mode 100644
index 0000000..a4cd384
--- /dev/null
+++ b/t/ifndef.at
@@ -0,0 +1,60 @@
+# This file is part of xenv                         -*- autotest -*-
+# Copyright (C) 2021 Sergey Poznyakoff
+#
+# Xenv is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# Xenv is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with xenv. If not, see <http://www.gnu.org/licenses/>. */
+
+AT_SETUP([$$ifndef])
+AT_DATA([input],
+[Duis aute irure dolor in reprehenderit in voluptate velit esse
+$$ifndef X
+cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat
+$$else
+$$ ifndef Y
+...
+$$ endif
+$$ endif
+cupidatat non proident, sunt in culpa qui officia deserunt mollit
+anim id est laborum.
+])
+
+AT_CHECK([unset X Y
+xenv input
+],
+[0],
+[Duis aute irure dolor in reprehenderit in voluptate velit esse
+cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat
+cupidatat non proident, sunt in culpa qui officia deserunt mollit
+anim id est laborum.
+])
+
+AT_CHECK([unset Y
+X= xenv input
+],
+[0],
+[Duis aute irure dolor in reprehenderit in voluptate velit esse
+...
+cupidatat non proident, sunt in culpa qui officia deserunt mollit
+anim id est laborum.
+])
+
+AT_CHECK([
+X= Y= xenv input
+],
+[0],
+[Duis aute irure dolor in reprehenderit in voluptate velit esse
+cupidatat non proident, sunt in culpa qui officia deserunt mollit
+anim id est laborum.
+])
+
+AT_CLEANUP
diff --git a/t/ifnset.at b/t/ifnset.at
new file mode 100644
index 0000000..bcfe5a7
--- /dev/null
+++ b/t/ifnset.at
@@ -0,0 +1,60 @@
+# This file is part of xenv                         -*- autotest -*-
+# Copyright (C) 2021 Sergey Poznyakoff
+#
+# Xenv is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# Xenv is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with xenv. If not, see <http://www.gnu.org/licenses/>. */
+
+AT_SETUP([$$ifnset])
+AT_DATA([input],
+[Duis aute irure dolor in reprehenderit in voluptate velit esse
+$$ifnset X
+cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat
+$$else
+$$ ifnset Y
+...
+$$ endif
+$$ endif
+cupidatat non proident, sunt in culpa qui officia deserunt mollit
+anim id est laborum.
+])
+
+AT_CHECK([unset X Y
+xenv input
+],
+[0],
+[Duis aute irure dolor in reprehenderit in voluptate velit esse
+cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat
+cupidatat non proident, sunt in culpa qui officia deserunt mollit
+anim id est laborum.
+])
+
+AT_CHECK([unset Y
+X=1 xenv input
+],
+[0],
+[Duis aute irure dolor in reprehenderit in voluptate velit esse
+...
+cupidatat non proident, sunt in culpa qui officia deserunt mollit
+anim id est laborum.
+])
+
+AT_CHECK([
+X=1 Y=1 xenv input
+],
+[0],
+[Duis aute irure dolor in reprehenderit in voluptate velit esse
+cupidatat non proident, sunt in culpa qui officia deserunt mollit
+anim id est laborum.
+])
+
+AT_CLEANUP
diff --git a/t/ifset.at b/t/ifset.at
new file mode 100644
index 0000000..f7f7ac1
--- /dev/null
+++ b/t/ifset.at
@@ -0,0 +1,60 @@
+# This file is part of xenv                         -*- autotest -*-
+# Copyright (C) 2021 Sergey Poznyakoff
+#
+# Xenv is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# Xenv is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with xenv. If not, see <http://www.gnu.org/licenses/>. */
+
+AT_SETUP([$$ifset])
+AT_DATA([input],
+[Duis aute irure dolor in reprehenderit in voluptate velit esse
+$$ifset X
+cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat
+$$else
+$$ ifset Y
+...
+$$ endif
+$$ endif
+cupidatat non proident, sunt in culpa qui officia deserunt mollit
+anim id est laborum.
+])
+
+AT_CHECK([unset X Y
+xenv input
+],
+[0],
+[Duis aute irure dolor in reprehenderit in voluptate velit esse
+cupidatat non proident, sunt in culpa qui officia deserunt mollit
+anim id est laborum.
+])
+
+AT_CHECK([unset X
+Y=1 xenv input
+],
+[0],
+[Duis aute irure dolor in reprehenderit in voluptate velit esse
+...
+cupidatat non proident, sunt in culpa qui officia deserunt mollit
+anim id est laborum.
+])
+
+AT_CHECK([
+X=1 xenv input
+],
+[0],
+[Duis aute irure dolor in reprehenderit in voluptate velit esse
+cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat
+cupidatat non proident, sunt in culpa qui officia deserunt mollit
+anim id est laborum.
+])
+
+AT_CLEANUP
diff --git a/t/quote.at b/t/quote.at
new file mode 100644
index 0000000..a10d09f
--- /dev/null
+++ b/t/quote.at
@@ -0,0 +1,54 @@
+# This file is part of xenv                         -*- autotest -*-
+# Copyright (C) 2021 Sergey Poznyakoff
+#
+# Xenv is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# Xenv is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with xenv. If not, see <http://www.gnu.org/licenses/>. */
+
+AT_SETUP([Quoting])
+AT_DATA([input],[
+Anything appearing between \$( and ) is quoted.
+Quoted $(text keeps track of (balanced ()) parentheses to
+find the right closing) one.
+$(Unbalanced parentheses can be quoted like that: \).
+
+No variable expansion occurs within quotes, e.g.: $X.
+
+Preprocessed statements and comments are retained as well:
+
+  $$ifset X
+
+  ${* comment *}
+
+After closing parenthesis, normal preprocessing is restored:) $X.
+])
+
+AT_CHECK([X=TEXT xenv input],
+[0],
+[
+Anything appearing between $( and ) is quoted.
+Quoted text keeps track of (balanced ()) parentheses to
+find the right closing one.
+Unbalanced parentheses can be quoted like that: ).
+
+No variable expansion occurs within quotes, e.g.: $X.
+
+Preprocessed statements and comments are retained as well:
+
+  $$ifset X
+
+  ${* comment *}
+
+After closing parenthesis, normal preprocessing is restored: TEXT.
+])
+
+AT_CLEANUP
diff --git a/t/set.at b/t/set.at
new file mode 100644
index 0000000..0c840e4
--- /dev/null
+++ b/t/set.at
@@ -0,0 +1,34 @@
+# This file is part of xenv                         -*- autotest -*-
+# Copyright (C) 2021 Sergey Poznyakoff
+#
+# Xenv is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# Xenv is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with xenv. If not, see <http://www.gnu.org/licenses/>. */
+
+AT_SETUP([$$set])
+AT_CHECK([
+AT_DATA([input],
+[$$set X
+  $$ set Y "string \"nested string\" test"
+
+X is ${X+set (value '$X')}
+Y is ${Y+set (value '$Y')}
+])
+unset X Y
+xenv input
+],
+[0],
+[
+X is set (value '')
+Y is set (value 'string "nested string" test')
+])
+AT_CLEANUP
diff --git a/t/simple.at b/t/simple.at
new file mode 100644
index 0000000..74be3de
--- /dev/null
+++ b/t/simple.at
@@ -0,0 +1,54 @@
+# This file is part of xenv                         -*- autotest -*-
+# Copyright (C) 2021 Sergey Poznyakoff
+#
+# Xenv is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# Xenv is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with xenv. If not, see <http://www.gnu.org/licenses/>. */
+
+AT_SETUP([Simple expansion])
+AT_DATA([input],
+[foo is $X_FOO, bar is $X_BAR.
+])
+AT_CHECK([
+unset X_FOO
+unset X_BAR
+xenv input],
+[0],
+[foo is , bar is .
+])
+AT_CHECK([
+unset X_FOO
+unset X_BAR
+xenv -u input],
+[65],
+[foo is , bar is .
+],
+[input:1: variable X_FOO not defined
+input:1: variable X_BAR not defined
+])
+AT_CHECK([
+unset X_FOO
+unset X_BAR
+xenv -ur input],
+[65],
+[foo is $X_FOO, bar is $X_BAR.
+],
+[input:1: variable X_FOO not defined
+input:1: variable X_BAR not defined
+])
+AT_CHECK([
+X_FOO=baz X_BAR=qux xenv -u input],
+[0],
+[foo is baz, bar is qux.
+])
+
+AT_CLEANUP
\ No newline at end of file
diff --git a/t/ternary.at b/t/ternary.at
new file mode 100644
index 0000000..03888ef
--- /dev/null
+++ b/t/ternary.at
@@ -0,0 +1,57 @@
+# This file is part of xenv                         -*- autotest -*-
+# Copyright (C) 2021 Sergey Poznyakoff
+#
+# Xenv is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# Xenv is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with xenv. If not, see <http://www.gnu.org/licenses/>. */
+
+AT_SETUP([Ternary operator])
+AT_DATA([input],
+[Lorem ipsum ${OBJ|dolor|fulgor} sit amet, ${GBR:|consectetur|obliviscetur} adipiscing elit,
+sed ${LIM:||do }eiusmod tempor ${ALT:|incididunt} ut labore et dolore magna aliqua.
+])
+
+AT_CHECK([
+unset OBJ GBR LIM ALT
+xenv input
+],
+[0],
+[Lorem ipsum fulgor sit amet, obliviscetur adipiscing elit,
+sed do eiusmod tempor  ut labore et dolore magna aliqua.
+])
+AT_CHECK([
+OBJ=
+GBR=
+LIM=
+ALT=
+export OBJ GBR LIM ALT
+xenv input
+],
+[0],
+[Lorem ipsum dolor sit amet, obliviscetur adipiscing elit,
+sed do eiusmod tempor  ut labore et dolore magna aliqua.
+])
+
+AT_CHECK([
+OBJ=1
+GBR=1
+LIM=1
+ALT=1
+export OBJ GBR LIM ALT
+xenv input
+],
+[0],
+[Lorem ipsum dolor sit amet, consectetur adipiscing elit,
+sed eiusmod tempor incididunt ut labore et dolore magna aliqua.
+])
+
+AT_CLEANUP
diff --git a/t/testsuite.at b/t/testsuite.at
new file mode 100644
index 0000000..ecdb3fe
--- /dev/null
+++ b/t/testsuite.at
@@ -0,0 +1,34 @@
+# This file is part of xenv                         -*- autotest -*-
+# Copyright (C) 2021 Sergey Poznyakoff
+#
+# Xenv is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 3 of the License, or (at your
+# option) any later version.
+#
+# Xenv is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.