patch 7.4.1092

Problem:    It is not simple to test for an exception and give a proper error
            message.
Solution:   Add assert_exception().

runtime/doc/eval.txt

@@ -1750,9 +1750,10 @@ arglistid( [{winnr} [, {tabnr}]])
 				Number	argument list id
 argv( {nr})			String	{nr} entry of the argument list
 argv( )				List	the argument list
-assert_equal( {exp}, {act} [, {msg}]) none    assert that {exp} equals {act}
-assert_false( {actual} [, {msg}])     none    assert that {actual} is false
-assert_true( {actual} [, {msg}])      none    assert that {actual} is true
+assert_equal( {exp}, {act} [, {msg}]) none  assert {exp} equals {act}
+assert_exception({error} [, {msg}])   none  assert {error} is in v:exception
+assert_false( {actual} [, {msg}])     none  assert {actual} is false
+assert_true( {actual} [, {msg}])      none  assert {actual} is true
 asin( {expr})			Float	arc sine of {expr}
 atan( {expr})			Float	arc tangent of {expr}
 atan2( {expr}, {expr})		Float   arc tangent of {expr1} / {expr2}
@@ -2179,7 +2180,7 @@ argv([{nr}])	The result is the {nr}th file in the argument list of the
 		returned.
 
 							*assert_equal()*
-assert_equal({expected}, {actual}, [, {msg}])
+assert_equal({expected}, {actual} [, {msg}])
 		When {expected} and {actual} are not equal an error message is
 		added to |v:errors|.
 		There is no automatic conversion, the String "4" is different
@@ -2193,18 +2194,31 @@ assert_equal({expected}, {actual}, [, {msg}])
 <		Will result in a string to be added to |v:errors|:
 	test.vim line 12: Expected 'foo' but got 'bar' ~
 
-assert_false({actual}, [, {msg}])				*assert_false()*
+assert_exception({error} [, {msg}])			*assert_exception()*
+		When v:exception does not contain the string {error} an error
+		message is added to |v:errors|.
+		This can be used to assert that a command throws an exception.
+		Using the error number, followed by a colon, avoids problems
+		with translations: >
+			try
+			  commandthatfails
+			  call assert_false(1, 'command should have failed')
+			catch
+			  call assert_exception('E492:')
+			endtry
+
+assert_false({actual} [, {msg}])				*assert_false()*
 		When {actual} is not false an error message is added to
-		|v:errors|, like with |assert_equal()|..
+		|v:errors|, like with |assert_equal()|.
 		A value is false when it is zero. When "{actual}" is not a
 		number the assert fails.
 		When {msg} is omitted an error in the form "Expected False but
 		got {actual}" is produced.
 
-assert_true({actual}, [, {msg}])				*assert_true()*
+assert_true({actual} [, {msg}])					*assert_true()*
 		When {actual} is not true an error message is added to
-		|v:errors|, like with |assert_equal()|..
-		A value is true when it is a non-zeron number.  When {actual}
+		|v:errors|, like with |assert_equal()|.
+		A value is true when it is a non-zero number.  When {actual}
 		is not a number the assert fails.
 		When {msg} is omitted an error in the form "Expected True but
 		got {actual}" is produced.

src/eval.c

@@ -475,6 +475,7 @@ static void f_argidx __ARGS((typval_T *argvars, typval_T *rettv));
 static void f_arglistid __ARGS((typval_T *argvars, typval_T *rettv));
 static void f_argv __ARGS((typval_T *argvars, typval_T *rettv));
 static void f_assert_equal __ARGS((typval_T *argvars, typval_T *rettv));
+static void f_assert_exception __ARGS((typval_T *argvars, typval_T *rettv));
 static void f_assert_false __ARGS((typval_T *argvars, typval_T *rettv));
 static void f_assert_true __ARGS((typval_T *argvars, typval_T *rettv));
 #ifdef FEAT_FLOAT
@@ -8088,6 +8089,7 @@ static struct fst
     {"asin",		1, 1, f_asin},	/* WJMc */
 #endif
     {"assert_equal",	2, 3, f_assert_equal},
+    {"assert_exception", 1, 2, f_assert_exception},
     {"assert_false",	1, 2, f_assert_false},
     {"assert_true",	1, 2, f_assert_true},
 #ifdef FEAT_FLOAT
@@ -9269,6 +9271,35 @@ f_assert_equal(argvars, rettv)
     }
 }
 
+/*
+ * "assert_exception(string[, msg])" function
+ */
+    static void
+f_assert_exception(argvars, rettv)
+    typval_T	*argvars;
+    typval_T	*rettv UNUSED;
+{
+    garray_T	ga;
+    char	*error;
+
+    error = (char *)get_tv_string_chk(&argvars[0]);
+    if (vimvars[VV_EXCEPTION].vv_str == NULL)
+    {
+	prepare_assert_error(&ga);
+	ga_concat(&ga, (char_u *)"v:exception is not set");
+	assert_error(&ga);
+	ga_clear(&ga);
+    }
+    else if (strstr((char *)vimvars[VV_EXCEPTION].vv_str, error) == NULL)
+    {
+	prepare_assert_error(&ga);
+	fill_assert_error(&ga, &argvars[1], NULL, &argvars[0],
+						&vimvars[VV_EXCEPTION].vv_tv);
+	assert_error(&ga);
+	ga_clear(&ga);
+    }
+}
+
 /*
  * Common for assert_true() and assert_false().
  */

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1092,
 /**/
     1091,
 /**/