vim-patch:8.2.1631: test_fails() does not check the context of the line number

Problem:    test_fails() does not check the context of the line number.
Solution:   Use another argument to specify the context of the line number.

https://github.com/vim/vim/commit/9bd5d879c2ecfbdbb168b090e12f4b89724a302e

Co-authored-by: Bram Moolenaar <Bram@vim.org>

5 files changed, 28 insertions, 11 deletions

diff --git a/runtime/doc/testing.txt b/runtime/doc/testing.txt
index 6d138de6c0..56e0dad656 100644
--- a/runtime/doc/testing.txt
+++ b/runtime/doc/testing.txt
@@ -100,7 +100,7 @@ assert_exception({error} [, {msg}])			*assert_exception()*
 			endtry
 <
 							*assert_fails()*
-assert_fails({cmd} [, {error} [, {msg} [, {lnum}]]])
+assert_fails({cmd} [, {error} [, {msg} [, {lnum} [, {context}]]]])
 		Run {cmd} and add an error message to |v:errors| if it does
 		NOT produce an error or when {error} is not found in the
 		error message.  Also see |assert-return|.
@@ -127,6 +127,10 @@ assert_fails({cmd} [, {error} [, {msg} [, {lnum}]]])
 		the line number at which the error was reported. That can be
 		the line number in a function or in a script.
 
+		When {context} is present it is used as a pattern and matched
+		against the context (script name or function name) where
+		{lnum} is located in.
+
 		Note that beeping is not considered an error, and some failing
 		commands only beep.  Use |assert_beeps()| for those.
 
diff --git a/src/nvim/eval.lua b/src/nvim/eval.lua
index 5952267c02..61e7f99afd 100644
--- a/src/nvim/eval.lua
+++ b/src/nvim/eval.lua
@@ -38,7 +38,7 @@ return {
     assert_equal={args={2, 3}, base=2},
     assert_equalfile={args={2, 3}, base=1},
     assert_exception={args={1, 2}},
-    assert_fails={args={1, 4}, base=1},
+    assert_fails={args={1, 5}, base=1},
     assert_false={args={1, 2}, base=1},
     assert_inrange={args={3, 4}, base=3},
     assert_match={args={2, 3}, base=2},
diff --git a/src/nvim/globals.h b/src/nvim/globals.h
index f3e9336baa..14266fc859 100644
--- a/src/nvim/globals.h
+++ b/src/nvim/globals.h
@@ -198,6 +198,7 @@ EXTERN bool emsg_severe INIT(= false);      // use message of next of several
 EXTERN bool emsg_assert_fails_used INIT(= false);
 EXTERN char *emsg_assert_fails_msg INIT(= NULL);
 EXTERN long emsg_assert_fails_lnum INIT(= 0);
+EXTERN char *emsg_assert_fails_context INIT(= NULL);
 
 EXTERN bool did_endif INIT(= false);        // just had ":endif"
 EXTERN dict_T vimvardict;                   // Dictionary with v: variables
diff --git a/src/nvim/message.c b/src/nvim/message.c
index c95968afb4..fa1c8036e6 100644
--- a/src/nvim/message.c
+++ b/src/nvim/message.c
@@ -666,6 +666,8 @@ static bool emsg_multiline(const char *s, bool multiline)
     if (emsg_assert_fails_used && emsg_assert_fails_msg == NULL) {
       emsg_assert_fails_msg = xstrdup(s);
       emsg_assert_fails_lnum = SOURCING_LNUM;
+      xfree(emsg_assert_fails_context);
+      emsg_assert_fails_context = xstrdup(SOURCING_NAME == NULL ? "" : SOURCING_NAME);
     }
 
     // set "v:errmsg", also when using ":silent! cmd"
diff --git a/src/nvim/testing.c b/src/nvim/testing.c
index 4ab1367f26..9dfd828a67 100644
--- a/src/nvim/testing.c
+++ b/src/nvim/testing.c
@@ -500,7 +500,7 @@ void f_assert_fails(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     char buf[NUMBUFLEN];
     const char *expected;
     bool error_found = false;
-    bool lnum_error_found = false;
+    int error_found_index = 1;
     char *actual = emsg_assert_fails_msg == NULL ? "[unknown]" : emsg_assert_fails_msg;
 
     if (argvars[1].v_type == VAR_STRING) {
@@ -530,26 +530,36 @@ void f_assert_fails(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     }
 
     if (!error_found && argvars[2].v_type != VAR_UNKNOWN
-        && argvars[3].v_type == VAR_NUMBER
-        && argvars[3].vval.v_number >= 0
-        && argvars[3].vval.v_number != emsg_assert_fails_lnum) {
-      error_found = true;
-      lnum_error_found = true;
+        && argvars[3].v_type == VAR_NUMBER) {
+      if (argvars[3].vval.v_number >= 0
+          && argvars[3].vval.v_number != emsg_assert_fails_lnum) {
+        error_found = true;
+        error_found_index = 3;
+      }
+      if (!error_found && argvars[4].v_type == VAR_STRING
+          && argvars[4].vval.v_string != NULL
+          && !pattern_match(argvars[4].vval.v_string,
+                            emsg_assert_fails_context, false)) {
+        error_found = true;
+        error_found_index = 4;
+      }
     }
 
     if (error_found) {
       typval_T actual_tv;
       prepare_assert_error(&ga);
-      if (lnum_error_found) {
+      if (error_found_index == 3) {
         actual_tv.v_type = VAR_NUMBER;
         actual_tv.vval.v_number = emsg_assert_fails_lnum;
+      } else if (error_found_index == 4) {
+        actual_tv.v_type = VAR_STRING;
+        actual_tv.vval.v_string = emsg_assert_fails_context;
       } else {
         actual_tv.v_type = VAR_STRING;
         actual_tv.vval.v_string = actual;
       }
       fill_assert_error(&ga, &argvars[2], NULL,
-                        &argvars[lnum_error_found ? 3 : 1],
-                        &actual_tv, ASSERT_OTHER);
+                        &argvars[error_found_index], &actual_tv, ASSERT_OTHER);
       ga_concat(&ga, ": ");
       assert_append_cmd_or_arg(&ga, argvars, cmd);
       assert_error(&ga);