feat: better error handling for duplicate edges and fixed tests

testdata/includes/Taskfile.yml

@@ -6,13 +6,13 @@ includes:
   included_without_dir:
     taskfile:  ./module1
   included_taskfile_without_dir:
-    taskfile:  ./module1/Taskfile.yml
-  included_with_dir:
-    taskfile:  ./module2
-    dir:  ./module2
-  included_taskfile_with_dir:
     taskfile:  ./module2/Taskfile.yml
-    dir:  ./module2
+  included_with_dir:
+    taskfile:  ./module3
+    dir:  ./module3
+  included_taskfile_with_dir:
+    taskfile:  ./module4/Taskfile.yml
+    dir:  ./module4
   included_os: ./Taskfile_{{OS}}.yml
 
 tasks:

testdata/includes/module1/Taskfile.yml

@@ -1,10 +1,6 @@
 version: '3'
 
 tasks:
-  gen_dir:
-    cmds:
-      - echo included_directory_without_dir > included_directory_without_dir.txt
-
   gen_file:
     cmds:
       - echo included_taskfile_without_dir > included_taskfile_without_dir.txt

testdata/includes/module2/Taskfile.yml

@@ -3,8 +3,4 @@ version: '3'
 tasks:
   gen_dir:
     cmds:
-      - echo included_directory_with_dir > included_directory_with_dir.txt
-
-  gen_file:
-    cmds:
-      - echo included_taskfile_with_dir > included_taskfile_with_dir.txt
+      - echo included_directory_without_dir > included_directory_without_dir.txt

testdata/includes/module3/Taskfile.yml

@@ -0,0 +1,6 @@
+version: '3'
+
+tasks:
+  gen_file:
+    cmds:
+      - echo included_taskfile_with_dir > included_taskfile_with_dir.txt

testdata/includes/module4/Taskfile.yml

@@ -0,0 +1,6 @@
+version: '3'
+
+tasks:
+  gen_dir:
+    cmds:
+      - echo included_directory_with_dir > included_directory_with_dir.txt