diff --git a/tests/03-empty-doc-meta.cpp b/tests/03-empty-doc-meta.cpp
index 72efc4b..aec76c9 100644
--- a/tests/03-empty-doc-meta.cpp
+++ b/tests/03-empty-doc-meta.cpp
@@ -38,7 +38,7 @@ int main(int argc, char** argv)
 	d.meta().contact = "platform@kruzhok.org";
 	d.meta().description = "1\n2\n3"; 
 	d.meta().version = "0.1";
-	d.meta().date = "2024-04-14 11:22";
+	d.meta().date = "2024-04-14T11:22:00";
 	d.meta().markup_language = "html";
 	d.meta().transition_order_flag = true; // exit first
 	d.meta().event_propagation_flag = true; // propagate
diff --git a/tests/03-output.graphml b/tests/03-output.graphml
index 634263f..7e8d458 100644
--- a/tests/03-output.graphml
+++ b/tests/03-output.graphml
@@ -49,7 +49,7 @@ description/ 1
 
 version/ 0.1
 
-date/ 2024-04-14 11:22
+date/ 2024-04-14T11:22:00
 
 markupLanguage/ html
 
diff --git a/tests/04-output.txt b/tests/04-output.txt
index 39e45c0..628b803 100644
--- a/tests/04-output.txt
+++ b/tests/04-output.txt
@@ -1,6 +1,6 @@
 Document: {id: '', name: 'Test document', format: 'Cyberiada-GraphML-1.0', meta: {standard version: '1.0', platform name: 'Berloga', platform version: '1.4', platform language: 'script', target system: 'Unit', name: 'Test document', author: 'Author', contact: 'platform@kruzhok.org', description: '1
 2
-3', version: '0.1', date: '2024-04-14 11:22', markup language: 'html', transition order: exit first, event propagation: propagate events}, elements: {State Machine: {id: 'G0', name: 'SM', elements: {Formal Comment: {id: 'nMeta', name: 'CGML_META', body: 'standardVersion/ 1.0
+3', version: '0.1', date: '2024-04-14T11:22:00', markup language: 'html', transition order: exit first, event propagation: propagate events}, elements: {State Machine: {id: 'G0', name: 'SM', elements: {Formal Comment: {id: 'nMeta', name: 'CGML_META', body: 'standardVersion/ 1.0
 
 platform/ Berloga
 
@@ -22,7 +22,7 @@ description/ 1
 
 version/ 0.1
 
-date/ 2024-04-14 11:22
+date/ 2024-04-14T11:22:00
 
 markupLanguage/ html
 
diff --git a/tests/04-read-meta.cpp b/tests/04-read-meta.cpp
index 23a700f..21f0574 100644
--- a/tests/04-read-meta.cpp
+++ b/tests/04-read-meta.cpp
@@ -41,7 +41,7 @@ int main(int argc, char** argv)
 		CYB_ASSERT(d.meta().contact == "platform@kruzhok.org");
 		CYB_ASSERT(d.meta().description == "1\n2\n3"); 
 		CYB_ASSERT(d.meta().version == "0.1");
-		CYB_ASSERT(d.meta().date == "2024-04-14 11:22");
+		CYB_ASSERT(d.meta().date == "2024-04-14T11:22:00");
 		CYB_ASSERT(d.meta().markup_language == "html");
 		CYB_ASSERT(d.meta().transition_order_flag); // exit first
 		CYB_ASSERT(d.meta().event_propagation_flag); // propagate
diff --git a/tests/04-read-meta.test-input.graphml b/tests/04-read-meta.test-input.graphml
index d093897..47e8a18 100644
--- a/tests/04-read-meta.test-input.graphml
+++ b/tests/04-read-meta.test-input.graphml
@@ -48,7 +48,7 @@ description/ 1
 
 version/ 0.1
 
-date/ 2024-04-14 11:22
+date/ 2024-04-14T11:22:00
 
 markupLanguage/ html