diff --git a/bake/tests/test_bakefile.py b/bake/tests/test_bakefile.py
index 5306517..c5d2a70 100644
--- a/bake/tests/test_bakefile.py
+++ b/bake/tests/test_bakefile.py
@@ -1,18 +1,18 @@
 def test_echo(bake):
     c = bake("echo", fixture="1")
-    assert "kenneth" in c.out
+    assert "kenneth" in c.err
 
 
 def test_first_level_dep(bake):
     c = bake("needs-echo", fixture="1")
-    assert "kenneth" in c.out
+    assert "kenneth" in c.err
 
 
 def test_second_level_dep(bake):
     c = bake("needs-needs", fixture="1")
-    assert "kenneth" in c.out
+    assert "kenneth" in c.err
 
 
 def test_python_invocation(bake):
     c = bake("python", fixture="1")
-    assert "wow" in c.out
+    assert "wow" in c.err
diff --git a/bake/tests/test_filters.py b/bake/tests/test_filters.py
index 4e35565..f90e1ae 100644
--- a/bake/tests/test_filters.py
+++ b/bake/tests/test_filters.py
@@ -1,30 +1,30 @@
-def test_confirm(bake):
-    c = bake("kinda-dangerous", fixture="2", block=False)
+def test_confirm(bake_i):
+    c = bake_i("kinda-dangerous", fixture="2", block=False)
     c.expect(":", timeout=0.5)
     c.send("N\n")
     c.block()
-    assert "Aborted!" in c.out
+    assert "Aborted!" in c.err
 
 
-def test_confirm_secure(bake):
-    c = bake("really-dangerous", fixture="2", block=False)
+def test_confirm_secure(bake_i):
+    c = bake_i("really-dangerous", fixture="2", block=False)
     c.expect(":", timeout=0.5)
     c.send("4222\n")
     c.block()
-    assert "Wrong answer!" in c.out
+    assert "Wrong answer!" in c.err
 
 
-def test_confirm_dep(bake):
-    c = bake("mostly-harmless", fixture="2", block=False)
+def test_confirm_dep(bake_i):
+    c = bake_i("mostly-harmless", fixture="2", block=False)
     c.expect(":", timeout=0.5)
     c.send("N\n")
     c.block()
-    assert "Aborted!" in c.out
+    assert "Aborted!" in c.err
 
 
-def test_confirm_secure(bake):
-    c = bake("mostly-dangerous", fixture="2", block=False)
+def test_confirm_secure(bake_i):
+    c = bake_i("mostly-dangerous", fixture="2", block=False)
     c.expect(":", timeout=0.5)
     c.send("4222\n")
     c.block()
-    assert "Wrong answer!" in c.out
+    assert "Wrong answer!" in c.err
diff --git a/bake/tests/test_graph.py b/bake/tests/test_graph.py
new file mode 100644
index 0000000..e69de29