testing/tcl_commands: test target create, cget, configure

Introduce basic testing of error-handling in target configuration
related commands.

The tests can be run via `make check` when JTAG `dummy` adapter is
enabled.

Change-Id: Id0f382046dd70007d8e696d82d2396a7ccab7a33
Signed-off-by: Evgeniy Naydanov <evgeniy.naydanov@syntacore.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/8644
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

testing/tcl_commands/utils.tcl

@@ -0,0 +1,80 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+namespace eval testing_helpers {
+
+	proc test_failure message {
+		echo $message
+		shutdown error
+	}
+
+	proc check_for_error {expctd_code msg_ptrn script} {
+		set code [catch {uplevel $script} msg]
+		set expanded_script [uplevel subst \"$script\"]
+		if {!$code} {
+			test_failure \
+				"'$expanded_script' finished successfully. \
+				Was expecting an error."
+		}
+		if {$expctd_code ne "" && $code != $expctd_code} {
+			test_failure \
+				"'$expanded_script' returned unexpected error code $code. \
+				Was expecting $expctd_code. Error message: '$msg'"
+		}
+		if {$msg_ptrn ne "" && ![regexp -- $msg_ptrn $msg]} {
+			test_failure \
+				"'$expanded_script' returned unexpected error message '$msg'. \
+				Was expecting '$msg_ptrn'. Error code: $code"
+		}
+	}
+
+	proc check_error_matches {pattern script} {
+		tailcall check_for_error {} $pattern $script
+	}
+
+	proc check_syntax_err script {
+		tailcall check_for_error -601 {} $script
+	}
+
+	proc check_matches {pattern script} {
+		set result [uplevel $script]
+		if {[regexp $pattern $result]} {return}
+		test_failure \
+			"'$script' produced unexpected result '$result'. \
+			Was expecting '$pattern'."
+	}
+
+	namespace export check_error_matches check_syntax_err check_matches
+}
+
+namespace eval configure_testing {
+
+	variable target_idx 0
+
+	proc unique_tgt_name {} {
+		variable target_idx
+		incr target_idx
+		return test_target$target_idx
+	}
+
+	proc target_create_first_args {} {
+		return "target create [unique_tgt_name] testee"
+	}
+
+	proc simple_configure_options {} {
+		return {
+			-work-area-virt 0
+			-work-area-phys 0
+			-work-area-size 1
+			-work-area-backup 0
+			-endian little
+			-coreid 1
+			-chain-position tap.cpu
+			-dbgbase 0
+			-rtos hwthread
+			-gdb-port 0
+			-gdb-max-connections 1
+		}
+	}
+
+	namespace export target_create_first_args simple_configure_options
+}