diff --git a/pkgs/development/python-modules/actdiag/default.nix b/pkgs/development/python-modules/actdiag/default.nix
index 6d04df9d9671..070bcd72ed4a 100644
--- a/pkgs/development/python-modules/actdiag/default.nix
+++ b/pkgs/development/python-modules/actdiag/default.nix
@@ -2,7 +2,7 @@
 , blockdiag
 , buildPythonPackage
 , fetchFromGitHub
-, nose
+, pynose
 , pytestCheckHook
 , pythonOlder
 , setuptools
@@ -11,24 +11,27 @@
 buildPythonPackage rec {
   pname = "actdiag";
   version = "3.0.0";
-  format = "setuptools";
+  pyproject = true;
 
   disabled = pythonOlder "3.7";
 
   src = fetchFromGitHub {
     owner = "blockdiag";
-    repo = pname;
-    rev = version;
+    repo = "actdiag";
+    rev = "refs/tags/${version}";
     hash = "sha256-WmprkHOgvlsOIg8H77P7fzEqxGnj6xaL7Df7urRkg3o=";
   };
 
-  propagatedBuildInputs = [
-    blockdiag
+  build-system = [
     setuptools
   ];
 
+  propagatedBuildInputs = [
+    blockdiag
+  ];
+
   nativeCheckInputs = [
-    nose
+    pynose
     pytestCheckHook
   ];
 
@@ -36,16 +39,23 @@ buildPythonPackage rec {
     "src/actdiag/tests/"
   ];
 
+  disabledTests = [
+    # AttributeError: 'TestRstDirectives' object has no attribute 'assertRegexpMatches'
+    "svg"
+    "noviewbox"
+  ];
+
   pythonImportsCheck = [
     "actdiag"
   ];
 
   meta = with lib; {
     description = "Generate activity-diagram image from spec-text file (similar to Graphviz)";
-    mainProgram = "actdiag";
     homepage = "http://blockdiag.com/";
+    changelog = "https://github.com/blockdiag/actdiag/blob/${version}/CHANGES.rst";
     license = licenses.asl20;
-    platforms = platforms.unix;
     maintainers = with maintainers; [ bjornfor ];
+    mainProgram = "actdiag";
+    platforms = platforms.unix;
   };
 }
diff --git a/pkgs/development/python-modules/blockdiag/default.nix b/pkgs/development/python-modules/blockdiag/default.nix
index 4444e3475946..47b598b306cb 100644
--- a/pkgs/development/python-modules/blockdiag/default.nix
+++ b/pkgs/development/python-modules/blockdiag/default.nix
@@ -1,31 +1,30 @@
 { lib
 , buildPythonPackage
 , docutils
+, ephem
 , fetchFromGitHub
 , fetchpatch
 , funcparserlib
-, nose
 , pillow
-, ephem
-, pythonOlder
+, pynose
 , pytestCheckHook
+, pythonOlder
 , reportlab
 , setuptools
 , webcolors
-, python
 }:
 
 buildPythonPackage rec {
   pname = "blockdiag";
   version = "3.0.0";
-  format = "setuptools";
+  pyproject = true;
 
   disabled = pythonOlder "3.7";
 
   src = fetchFromGitHub {
     owner = "blockdiag";
     repo = "blockdiag";
-    rev = version;
+    rev = "refs/tags/${version}";
     hash = "sha256-j8FoNUIJJOaahaol1MRPyY2jcPCEIlaAD4bmM2QKFFI=";
   };
 
@@ -38,18 +37,21 @@ buildPythonPackage rec {
     })
   ];
 
-  propagatedBuildInputs = [
+  build-system = [
     setuptools
+  ];
+
+  dependencies = [
+    docutils
     funcparserlib
     pillow
-    webcolors
     reportlab
-    docutils
+    webcolors
   ];
 
   nativeCheckInputs = [
     ephem
-    nose
+    pynose
     pytestCheckHook
   ];
 
@@ -68,10 +70,11 @@ buildPythonPackage rec {
 
   meta = with lib; {
     description = "Generate block-diagram image from spec-text file (similar to Graphviz)";
-    mainProgram = "blockdiag";
     homepage = "http://blockdiag.com/";
+    changelog = "https://github.com/blockdiag/blockdiag/blob/${version}/CHANGES.rst";
     license = licenses.asl20;
-    platforms = platforms.unix;
     maintainers = with maintainers; [ bjornfor ];
+    mainProgram = "blockdiag";
+    platforms = platforms.unix;
   };
 }
diff --git a/pkgs/development/python-modules/nwdiag/default.nix b/pkgs/development/python-modules/nwdiag/default.nix
index a35d6159731a..54bd6a1f9fea 100644
--- a/pkgs/development/python-modules/nwdiag/default.nix
+++ b/pkgs/development/python-modules/nwdiag/default.nix
@@ -2,7 +2,7 @@
 , blockdiag
 , fetchFromGitHub
 , buildPythonPackage
-, nose
+, pynose
 , pytestCheckHook
 , setuptools
 , pythonOlder
@@ -11,24 +11,27 @@
 buildPythonPackage rec {
   pname = "nwdiag";
   version = "3.0.0";
-  format = "setuptools";
+  pyproject = true;
 
   disabled = pythonOlder "3.7";
 
   src = fetchFromGitHub {
     owner = "blockdiag";
-    repo = pname;
-    rev = version;
+    repo = "nwdiag";
+    rev = "refs/tags/${version}";
     hash = "sha256-uKrdkXpL5YBr953sRsHknYg+2/WwrZmyDf8BMA2+0tU=";
   };
 
-  propagatedBuildInputs = [
-    blockdiag
+  build-system = [
     setuptools
   ];
 
+  dependencies = [
+    blockdiag
+  ];
+
   nativeCheckInputs = [
-    nose
+    pynose
     pytestCheckHook
   ];
 
@@ -37,8 +40,9 @@ buildPythonPackage rec {
   ];
 
   disabledTests = [
-    # UnicodeEncodeError: 'latin-1' codec can't encode...
-    "test_setup_inline_svg_is_true_with_multibytes"
+    # AttributeError: 'TestRstDirectives' object has no attribute 'assertRegexpMatches'
+    "svg"
+    "noviewbox"
   ];
 
   pythonImportsCheck = [
@@ -48,8 +52,10 @@ buildPythonPackage rec {
   meta = with lib; {
     description = "Generate network-diagram image from spec-text file (similar to Graphviz)";
     homepage = "http://blockdiag.com/";
+    changelog = "https://github.com/blockdiag/nwdiag/blob/${version}/CHANGES.rst";
     license = licenses.asl20;
-    platforms = platforms.unix;
     maintainers = with maintainers; [ bjornfor ];
+    mainProgram = "rackdiag";
+    platforms = platforms.unix;
   };
 }
diff --git a/pkgs/development/python-modules/seqdiag/default.nix b/pkgs/development/python-modules/seqdiag/default.nix
index bbf7cca1293a..8b8a89bd49db 100644
--- a/pkgs/development/python-modules/seqdiag/default.nix
+++ b/pkgs/development/python-modules/seqdiag/default.nix
@@ -2,7 +2,7 @@
 , blockdiag
 , buildPythonPackage
 , fetchFromGitHub
-, nose
+, pynose
 , pytestCheckHook
 , pythonOlder
 , setuptools
@@ -11,24 +11,27 @@
 buildPythonPackage rec {
   pname = "seqdiag";
   version = "3.0.0";
-  format = "setuptools";
+  pyproject = true;
 
   disabled = pythonOlder "3.7";
 
   src = fetchFromGitHub {
     owner = "blockdiag";
-    repo = pname;
-    rev = version;
+    repo = "seqdiag";
+    rev = "refs/tags/${version}";
     hash = "sha256-Dh9JMx50Nexi0q39rYr9MpkKmQRAfT7lzsNOXoTuphg=";
   };
 
-  propagatedBuildInputs = [
-    blockdiag
+  build-system = [
     setuptools
   ];
 
+  dependencies = [
+    blockdiag
+  ];
+
   nativeCheckInputs = [
-    nose
+    pynose
     pytestCheckHook
   ];
 
@@ -36,21 +39,17 @@ buildPythonPackage rec {
     "src/seqdiag/tests/"
   ];
 
-  disabledTests = [
-    # UnicodeEncodeError: 'latin-1' codec can't encode...
-    "test_setup_inline_svg_is_true_with_multibytes"
-  ];
-
   pythonImportsCheck = [
     "seqdiag"
   ];
 
   meta = with lib; {
     description = "Generate sequence-diagram image from spec-text file (similar to Graphviz)";
-    mainProgram = "seqdiag";
     homepage = "http://blockdiag.com/";
+    changelog = "https://github.com/blockdiag/seqdiag/blob/${version}/CHANGES.rst";
     license = licenses.asl20;
-    platforms = platforms.unix;
     maintainers = with maintainers; [ bjornfor ];
+    mainProgram = "seqdiag";
+    platforms = platforms.unix;
   };
 }