diff --git a/hmdl.schema.json b/hmdl.schema.json
index 8e6b49d..b6fde4e 100644
--- a/hmdl.schema.json
+++ b/hmdl.schema.json
@@ -7,17 +7,17 @@
 			"type": "object",
 			"additionalProperties": false,
 			"properties": {
-				"kind": {
-					"type": "string",
-					"enum": [
-						"minutely",
-						"hourly",
-						"daily"
-					]
+				"regular_interval": {
+					"description": "in seconds",
+					"type": "integer"
+				},
+				"attentive_interval": {
+					"description": "in seconds",
+					"type": "integer"
 				}
 			},
 			"required": [
-				"kind"
+				"regular_interval"
 			]
 		},
 		"notifications": {
@@ -171,6 +171,42 @@
 					},
 					{
 						"anyOf": [
+							{
+								"type": "object",
+								"additionalProperties": false,
+								"properties": {
+									"kind": {
+										"type": "string",
+										"const": "test"
+									},
+									"parameters": {
+										"type": "object",
+										"additionalProperties": false,
+										"properties": {
+											"condition": {
+												"type": "string",
+												"enum": [
+													"unknown",
+													"ok",
+													"warning",
+													"critical"
+												],
+												"default": "warning"
+											},
+											"output": {
+												"type": "string",
+												"default": ""
+											}
+										},
+										"required": [
+										]
+									}
+								},
+								"required": [
+									"kind",
+									"parameters"
+								]
+							},
 							{
 								"type": "object",
 								"additionalProperties": false,
diff --git a/source/check_kinds/_interface.py b/source/check_kinds/_interface.py
index c7b376b..00943d0 100644
--- a/source/check_kinds/_interface.py
+++ b/source/check_kinds/_interface.py
@@ -4,6 +4,6 @@ class interface_check_kind(object):
 		raise NotImplementedError
 	
 	
-	def run(self, check_data):
+	def run(self, parameters):
 		raise NotImplementedError
 
diff --git a/source/check_kinds/http_request.py b/source/check_kinds/http_request.py
index b674617..e78f734 100644
--- a/source/check_kinds/http_request.py
+++ b/source/check_kinds/http_request.py
@@ -22,22 +22,22 @@ class implementation_check_kind_http_request(interface_check_kind):
 	'''
 	[implementation]
 	'''
-	def run(self, check_data):
-		if (check_data["parameters"]["request"]["method"] == "GET"):
+	def run(self, parameters):
+		if (parameters["request"]["method"] == "GET"):
 			method_handled = True
 			try:
 				response = _requests.get(
-					check_data["parameters"]["request"]["target"]
+					parameters["request"]["target"]
 				)
 				error = None
 			except Exception as error_:
 				error = error_
 				response = None
-		elif (check_data["parameters"]["request"]["method"] == "POST"):
+		elif (parameters["request"]["method"] == "POST"):
 			method_handled = True
 			try:
 				response = _requests.post(
-					check_data["parameters"]["request"]["target"]
+					parameters["request"]["target"]
 				)
 				error = None
 			except Exception as error_:
@@ -49,21 +49,21 @@ class implementation_check_kind_http_request(interface_check_kind):
 		if (not method_handled):
 			return {
 				"condition": enum_condition.unknown,
-				"output": ("invalid HTTP request method: %s" % check_data["parameters"]["request"]["method"])
+				"output": ("invalid HTTP request method: %s" % parameters["request"]["method"])
 			}
 		else:
 			if (response is None):
 				return {
 					"condition": (
 						enum_condition.warning
-						if check_data["parameters"]["as_warning"] else
+						if parameters["as_warning"] else
 						enum_condition.critical
 					),
 					"output": "HTTP request failed",
 				}
 			else:
 				lines = []
-				for (key, value, ) in check_data["parameters"]["response"].items():
+				for (key, value, ) in parameters["response"].items():
 					if (key == "status_code"):
 						if ((value is None) or (response.status_code == value)):
 							pass
@@ -112,7 +112,7 @@ class implementation_check_kind_http_request(interface_check_kind):
 						if (len(lines) <= 0) else
 						(
 							enum_condition.warning
-							if check_data["parameters"]["as_warning"] else
+							if parameters["as_warning"] else
 							enum_condition.critical
 						)
 					),
diff --git a/source/check_kinds/script.py b/source/check_kinds/script.py
index 5df3e2e..7085048 100644
--- a/source/check_kinds/script.py
+++ b/source/check_kinds/script.py
@@ -14,9 +14,9 @@ class implementation_check_kind_script(interface_check_kind):
 	'''
 	[implementation]
 	'''
-	def run(self, check_data):
+	def run(self, parameters):
 		result = _subprocess.run(
-			[check_data["parameters"]["path"]] + check_data["parameters"]["arguments"],
+			[parameters["path"]] + parameters["arguments"],
 			capture_output = True
 		)
 		if (result.returncode == 0):
diff --git a/source/check_kinds/test.py b/source/check_kinds/test.py
new file mode 100644
index 0000000..c7a1946
--- /dev/null
+++ b/source/check_kinds/test.py
@@ -0,0 +1,24 @@
+class implementation_check_kind_test(interface_check_kind):
+
+	'''
+	[implementation]
+	'''
+	def normalize_conf_node(self, node):
+		return dict_merge(
+			{
+				"condition": condition_encode(enum_condition.warning),
+				"output": "",
+			},
+			node
+		)
+		
+	
+	'''
+	[implementation]
+	'''
+	def run(self, parameters):
+		return {
+			"condition": condition_decode(parameters["condition"]),
+			"output": parameters["output"]
+		}
+
diff --git a/source/main.py b/source/main.py
index 94e70d0..596807e 100644
--- a/source/main.py
+++ b/source/main.py
@@ -16,7 +16,7 @@ def state_decode(state_encoded):
 
 def conf_normalize_check(check_kind_implementations, defaults, name, node):
 	if ("kind" not in node):
-		raise ValueError("missing mandatory 'member' field 'kind'")
+		raise ValueError("missing mandatory 'check' field 'kind'")
 	else:
 		if (node["kind"] not in check_kind_implementations):
 			raise ValueError("unhandled kind: %s" % node["kind"])
@@ -45,8 +45,12 @@ def conf_normalize_defaults(node):
 	return dict_merge(
 		{
 			"active": True,
-			"schedule": {"kind": "hourly"},
-			"notifications": [],
+			"schedule": {
+				"regular_interval": (60 * 60),
+				"attentive_interval": (60 * 2),
+			},
+			"notifications": [
+			],
 		},
 		node
 	)
@@ -93,6 +97,14 @@ def main():
 		metavar = "<state-path>",
 		help = "path to the state file, which contains information about the recent checks; default: file in temporary directory, unique for the conf-path input"
 	)
+	argumentparser.add_argument(
+		"-x",
+		"--erase-state",
+		action = "store_true",
+		default = False,
+		dest = "erase_state",
+		help = "whether the state shall be deleted on start; this will cause that all checks are executed"
+	)
 	argumentparser.add_argument(
 		"-t",
 		"--threshold",
@@ -102,15 +114,6 @@ def main():
 		metavar = "<threshold>",
 		help = "how often a condition has to occur in order to be reported"
 	)
-	argumentparser.add_argument(
-		"-a",
-		"--awareness-interval",
-		type = int,
-		default = 120,
-		dest = "awareness_interval",
-		metavar = "<awareness-interval>",
-		help = "seconds to wait until starting the next run of a check, for which the condition has changed recently"
-	)
 	argumentparser.add_argument(
 		"-k",
 		"--keep-notifying",
@@ -120,7 +123,7 @@ def main():
 		help = "whether notifications shall be kept sending after the threshold has been surpassed"
 	)
 	argumentparser.add_argument(
-		"-x",
+		"-e",
 		"--expose-full-conf",
 		action = "store_true",
 		default = False,
@@ -146,6 +149,7 @@ def main():
 	
 	### load check kind implementations
 	check_kind_implementations = {
+		"test": implementation_check_kind_test(),
 		"script": implementation_check_kind_script(),
 		"http_request": implementation_check_kind_http_request(),
 	}
@@ -163,7 +167,11 @@ def main():
 		_sys.exit(1)
 	else:
 		### get state data
-		if (not _os.path.exists(state_path)):
+		if (
+			(not _os.path.exists(state_path))
+			or
+			args.erase_state
+		):
 			state_data = {}
 			file_write(state_path, _json.dumps(state_data, indent = "\t"))
 		else:
@@ -184,29 +192,15 @@ def main():
 				due = (
 					(old_item_state is None)
 					or
+					(old_item_state["condition"] != enum_condition.ok)
+					or
 					(
 						(old_item_state["count"] is not None)
 						and
-						((timestamp - old_item_state["timestamp"]) >= args.awareness_interval)
-					)
-					or
-					(
 						(
-							(check_data["schedule"]["kind"] == "minutely")
-							and
-							((timestamp - old_item_state["timestamp"]) >= (60))
-						)
-						or
-						(
-							(check_data["schedule"]["kind"] == "hourly")
-							and
-							((timestamp - old_item_state["timestamp"]) >= (60 * 60))
-						)
-						or
-						(
-							(check_data["schedule"]["kind"] == "daily")
-							and
-							((timestamp - old_item_state["timestamp"]) >= (60 * 60 * 24))
+							((timestamp - old_item_state["timestamp"]) >= check_data["schedule"]["regular_interval"])
+							or
+							((timestamp - old_item_state["timestamp"]) >= check_data["schedule"]["attentive_interval"])
 						)
 					)
 				)
@@ -223,7 +217,7 @@ def main():
 					)
 					
 					### execute check and set new state
-					result = check_kind_implementations[check_data["kind"]].run(check_data)
+					result = check_kind_implementations[check_data["kind"]].run(check_data["parameters"])
 					new_item_state = {
 						"timestamp": timestamp,
 						"condition": result["condition"],
diff --git a/test.hmdl.json b/test.hmdl.json
new file mode 100644
index 0000000..24a107a
--- /dev/null
+++ b/test.hmdl.json
@@ -0,0 +1,22 @@
+{
+	"defaults": {
+	},
+	"checks": {
+		"test": {
+			"schedule": {
+				"regular_interval": 12,
+				"attentive_interval": 5
+			},
+			"notifications": [
+				{
+					"kind": "console",
+					"parameters": {
+					}
+				}
+			],
+			"kind": "test",
+			"parameters": {
+			}
+		}
+	}
+}
diff --git a/todo.md b/todo.md
index 76e0678..246cfab 100644
--- a/todo.md
+++ b/todo.md
@@ -1,4 +1,7 @@
-- prevent parallel acces to state file?
-- more resililient checks
-- self check
-- notification channel "Matrix"
+- parallele Zugriffe auf die Zustands-Datei verhindern
+- fehlertolerantere Implementierung
+- Selbst-Test
+- Matrix als Benachrichtigungs-Kanal
+- JSON-Schema für Konfiguration von Programm erzeugen lassen
+- Möglichkeit dauerhaft laufen zulassen (evtl. als systemd-Dienst)
+- Versionierung
diff --git a/tools/build b/tools/build
index 7bc5afa..525ddb3 100755
--- a/tools/build
+++ b/tools/build
@@ -6,6 +6,7 @@ cat \
 	source/packages.py \
 	source/lib.py \
 	source/check_kinds/_interface.py \
+	source/check_kinds/test.py \
 	source/check_kinds/script.py \
 	source/check_kinds/http_request.py \
 	source/notification_channels/_interface.py \