1 files changed, 75 insertions, 2 deletions
diff --git a/unit-tests/directive-if.mk b/unit-tests/directive-if.mk
index 72d7d0e2d920..3b1d13c7a0c0 100644
--- a/unit-tests/directive-if.mk
+++ b/unit-tests/directive-if.mk
@@ -1,8 +1,81 @@
-# $NetBSD: directive-if.mk,v 1.2 2020/08/16 14:25:16 rillig Exp $
+# $NetBSD: directive-if.mk,v 1.7 2020/11/15 20:20:58 rillig Exp $
 #
 # Tests for the .if directive.
+#
+# See also:
+#	cond-*.mk
 
 # TODO: Implementation
 
+.if 0
+.  error
+.else
+.  info 0 evaluates to false.
+.endif
+
+.if 1
+.  info 1 evaluates to true.
+.else
+.  error
+.endif
+
+# There is no '.ifx'.
+#
+# The commit from 2005-05-01 intended to detect this situation, but it failed
+# to do this since the call to is_token had its arguments switched.  They were
+# expected as (str, token, token_len) but were actually passed as (token, str,
+# token_len).  This made is_token return true even if the directive was
+# directly followed by alphanumerical characters, which was wrong.  The
+# typical cases produced an error message such as "Malformed conditional
+# (x 123)", while the intended error message was "Unknown directive".
+#
+# Back at that time, the commits only modified the main code but did not add
+# the corresponding unit tests.  This allowed the bug to hide for more than
+# 15 years.
+#
+# Since 2020-11-10, the correct error message is produced.  The '.ifx' is no
+# longer interpreted as a variant of '.if', therefore the '.error' and '.else'
+# are interpreted as ordinary directives, producing the error messages
+# "if-less else" and "if-less endif".
+.ifx 123
+.  error
+.else
+.  error
+.endif
+
+# Missing condition.
+.if
+.  error
+.else
+.  error
+.endif
+
+# A plain word must not start with a '"'.  It may contain a embedded quotes
+# though, which are kept.  The quotes need not be balanced.  The next space
+# ends the word, and the remaining " || 1" is parsed as "or true".
+.if ${:Uplain"""""} == plain""""" || 1
+.  info Quotes in plain words are probably a mistake.
+# XXX: Accepting quotes in plain words is probably a mistake as well.
+.else
+.  error
+.endif
+
+.if0
+.  error
+.else
+.  info Don't do this, always put a space after a directive.
+.endif
+
+.if${:U-3}
+.  info Don't do this, always put a space after a directive.
+.else
+.  error
+.endif
+
+.if${:U-3}>-4
+.  info Don't do this, always put a space around comparison operators.
+.else
+.  error
+.endif
+
 all:
-	@:;