diff --git a/t/data/simple_carping_pipeline1.vtf b/t/data/simple_carping_pipeline1.vtf
new file mode 100644
index 000000000..28915b833
--- /dev/null
+++ b/t/data/simple_carping_pipeline1.vtf
@@ -0,0 +1,40 @@
+{
+	"description":	"minimal carping test pipeline - works, but I/O port names are poorly named. See log for warning",
+	"nodes":[
+	{	"id": "n1",
+		"type": "EXEC",
+		"cmd": "echo stuff",
+		"use_STDIN": 0,
+		"use_STDOUT": 1
+	},
+	{	"id": "n2",
+		"type": "EXEC",
+		"cmd": ["cat"],
+		"use_STDIN": 1,
+		"use_STDOUT": 1
+	},
+	{	"id": "m",
+		"type": "EXEC",
+		"cmd": ["echo", "stuff"],
+		"use_STDIN": false,
+		"use_STDOUT": true
+	},
+	{	"id": "d",
+		"type": "EXEC",
+		"cmd": "diff __IN1__ __IN2__",
+		"use_STDIN": 0,
+		"use_STDOUT": 0
+	}
+	],
+	"edges":[
+	{	"from": "n1",
+		"to": "n2"
+	},
+	{	"from": "n2",
+		"to": "d:__IN1__"
+	},
+	{	"from": "m",
+		"to": "d:__IN2__"
+	}
+	]
+}
diff --git a/t/data/simple_failing_io_pipeline1.vtf b/t/data/simple_failing_io_pipeline1.vtf
new file mode 100644
index 000000000..1b946d304
--- /dev/null
+++ b/t/data/simple_failing_io_pipeline1.vtf
@@ -0,0 +1,40 @@
+{
+	"description":	"minimal failing test pipeline. Port name in edge does not match one in node definition. Also carps about poorly named __IN1__ and __INN2__ ports",
+	"nodes":[
+	{	"id": "n1",
+		"type": "EXEC",
+		"cmd": "echo stuff",
+		"use_STDIN": 0,
+		"use_STDOUT": 1
+	},
+	{	"id": "n2",
+		"type": "EXEC",
+		"cmd": ["cat"],
+		"use_STDIN": 1,
+		"use_STDOUT": 1
+	},
+	{	"id": "m",
+		"type": "EXEC",
+		"cmd": ["echo", "stuff"],
+		"use_STDIN": false,
+		"use_STDOUT": true
+	},
+	{	"id": "d",
+		"type": "EXEC",
+		"cmd": "diff __IN1__ __IN2__",
+		"use_STDIN": 0,
+		"use_STDOUT": 0
+	}
+	],
+	"edges":[
+	{	"from": "n1",
+		"to": "n2"
+	},
+	{	"from": "n2",
+		"to": "d:__IN1__"
+	},
+	{	"from": "m",
+		"to": "d:__INN2__"
+	}
+	]
+}
diff --git a/t/data/simple_failing_io_pipeline2.vtf b/t/data/simple_failing_io_pipeline2.vtf
new file mode 100644
index 000000000..91b9b683f
--- /dev/null
+++ b/t/data/simple_failing_io_pipeline2.vtf
@@ -0,0 +1,40 @@
+{
+	"description":	"minimal failing test pipeline. Port names in edges match the node definitions, but are of the wrong type",
+	"nodes":[
+	{	"id": "n1",
+		"type": "EXEC",
+		"cmd": "echo stuff",
+		"use_STDIN": 0,
+		"use_STDOUT": 1
+	},
+	{	"id": "n2",
+		"type": "EXEC",
+		"cmd": ["cat"],
+		"use_STDIN": 1,
+		"use_STDOUT": 1
+	},
+	{	"id": "m",
+		"type": "EXEC",
+		"cmd": ["echo", "stuff"],
+		"use_STDIN": false,
+		"use_STDOUT": true
+	},
+	{	"id": "d",
+		"type": "EXEC",
+		"cmd": "diff __IN_1__ __OUT_2__",
+		"use_STDIN": 0,
+		"use_STDOUT": 0
+	}
+	],
+	"edges":[
+	{	"from": "n1",
+		"to": "n2"
+	},
+	{	"from": "n2",
+		"to": "d:__IN_1__"
+	},
+	{	"from": "m",
+		"to": "d:__OUT_2__"
+	}
+	]
+}
diff --git a/t/data/simple_failing_pipeline.vtf b/t/data/simple_failing_pipeline.vtf
index 16b0cbd85..dac3cb42d 100644
--- a/t/data/simple_failing_pipeline.vtf
+++ b/t/data/simple_failing_pipeline.vtf
@@ -1,5 +1,5 @@
 {
-	"description":	"minimal failing test pipeline",
+	"description":	"minimal failing test pipeline. Fails because of false in cmd. Also carps about poorly named __IN1__ and __IN2__ ports",
 	"nodes":[
 	{	"id": "n1",
 		"type": "EXEC",
diff --git a/t/data/simple_pipeline.vtf b/t/data/simple_pipeline.vtf
index d5f138f3d..631f2835d 100644
--- a/t/data/simple_pipeline.vtf
+++ b/t/data/simple_pipeline.vtf
@@ -21,7 +21,7 @@
 	},
 	{	"id": "d",
 		"type": "EXEC",
-		"cmd": "diff __IN1__ __IN2__",
+		"cmd": "diff __IN_1__ __IN_2__",
 		"use_STDIN": 0,
 		"use_STDOUT": 0
 	}
@@ -31,10 +31,10 @@
 		"to": "n2"
 	},
 	{	"from": "n2",
-		"to": "d:__IN1__"
+		"to": "d:__IN_1__"
 	},
 	{	"from": "m",
-		"to": "d:__IN2__"
+		"to": "d:__IN_2__"
 	}
 	]
 }