To/#380 null handling operation time

docs/readthedocs/models/models.rst

@@ -80,6 +80,12 @@ Equality Checks
       If you think you would benefit from such a method, please consider handing in an issue
       `here <https://github.com/ie3-institute/PowerSystemUtils/issues>`_.
 
+Conditional Parameters
+  Some of the models have conditional parameters. When reading model data from a data source, their respective factories for building these 
+  models can handle nulls and empty Strings (as well as any combination of those) safely. E.g.: When given parameters for a line's 
+  :code:`operationTime` where :code:`operationStartTime` and :code:`operationEndTime` are both :code:`null` or :code:`""`, the 
+  factory will build an always-on line model.
+
 *****
 Input
 *****

src/test/groovy/edu/ie3/datamodel/io/factory/input/AssetInputEntityFactoryTest.groovy

@@ -53,6 +53,39 @@ class AssetInputEntityFactoryTest extends Specification implements FactoryTestHe
 		}
 	}
 
+	def "An AssetInputFactory should parse a valid operated AssetInput correctly (with nulls and empty strings)"() {
+		given: "a system participant input type factory and model data"
+		def inputFactory = new TestAssetInputFactory()
+		Map<String, String> parameter = [
+			"uuid": "91ec3bcf-1777-4d38-af67-0bf7c9fa73c7",
+			"operatesfrom" : operatesfrom,
+			"operatesuntil": operatesuntil,
+			"id"  : "TestID"
+		]
+		def inputClass = TestAssetInput
+		def operatorInput = Mock(OperatorInput)
+
+		when:
+		Optional<TestAssetInput> input = inputFactory.get(new AssetInputEntityData(parameter, inputClass, operatorInput))
+
+		then:
+		input.present
+		input.get().getClass() == inputClass
+		((TestAssetInput) input.get()).with {
+			assert uuid == UUID.fromString(parameter["uuid"])
+			assert operationTime == OperationTime.notLimited()
+			assert operator == operatorInput
+			assert id == parameter["id"]
+		}
+
+		where:
+		operatesfrom	|  operatesuntil
+		null		    |  null
+		"" 				|  null
+		null			|  ""
+		"" 				|  ""
+	}
+
 	def "An AssetInputFactory should parse a valid operated AssetInput correctly (operation start time provided)"() {
 		given: "a system participant input type factory and model data"
 		def inputFactory = new TestAssetInputFactory()