diff --git a/api/s0_base.py b/api/s0_base.py
index a361435..bedcd28 100644
--- a/api/s0_base.py
+++ b/api/s0_base.py
@@ -163,7 +163,7 @@ def add_link(name: str, link_type: str, id: str, table_sql: str, table_undo_sql:
 
 
 def delete_link(name: str, link_type: str, id: str, table_sql: str, table_undo_sql: str) -> ChangeSet:
-    if not is_node(name, id):
+    if not is_link(name, id):
         return ChangeSet()
 
     with conn[name].cursor(row_factory=dict_row) as cur:
diff --git a/test_tjnetwork.py b/test_tjnetwork.py
index c910181..73d2629 100644
--- a/test_tjnetwork.py
+++ b/test_tjnetwork.py
@@ -62,6 +62,9 @@ class TestApi:
         assert change_set.added[0]['type'] == JUNCTION
         assert change_set.added[0]['id'] == "j1"
 
+        change_set = add_junction(p, "j1", 0.0, 10.0, 20.0)
+        assert len(change_set.added) == 0
+
         nodes = get_nodes(p)
         assert len(nodes) == 2
         assert nodes[0] == "j0"
@@ -72,6 +75,9 @@ class TestApi:
         assert change_set.deleted[0]['type'] == JUNCTION
         assert change_set.deleted[0]['id'] == "j1"
 
+        change_set = delete_junction(p, 'j1')
+        assert len(change_set.deleted) == 0
+
         nodes = get_nodes(p)
         assert len(nodes) == 1
         assert nodes[0] == "j0"
@@ -95,6 +101,9 @@ class TestApi:
         assert change_set.added[0]['type'] == RESERVOIR
         assert change_set.added[0]['id'] == "r0"
 
+        change_set = add_reservoir(p, "r0", 0.0, 10.0, 20.0)
+        assert len(change_set.added) == 0
+
         assert get_reservoir_head(p, 'r0') == 20.0
         change_set = set_reservoir_head(p, 'r0', 100.0)
         assert change_set.updated[0]['type'] == RESERVOIR
@@ -120,6 +129,9 @@ class TestApi:
         assert change_set.deleted[0]['type'] == RESERVOIR
         assert change_set.deleted[0]['id'] == "r0"
 
+        change_set = delete_reservoir(p, 'r0')
+        assert len(change_set.deleted) == 0
+
         self.leave(p)
 
     def test_tank(self):
@@ -137,6 +149,9 @@ class TestApi:
         assert change_set.added[0]['type'] == TANK
         assert change_set.added[0]['id'] == "t1"
 
+        change_set = add_tank(p, "t1", 0.0, 10.0, 20.0)
+        assert len(change_set.added) == 0
+
         tanks = get_nodes(p)
         assert len(tanks) == 2
         assert tanks[0] == 't0'
@@ -216,13 +231,141 @@ class TestApi:
         assert change_set.deleted[0]['type'] == TANK
         assert change_set.deleted[0]['id'] == "t1"
 
+        change_set = delete_tank(p, "t1")
+        assert len(change_set.deleted) == 0
+
         tanks = get_nodes(p)
         assert len(tanks) == 0
 
         self.leave(p)
 
     def test_pipe(self):
-        pass
+        p = "test_pipe"
+        self.enter(p)
+
+        change_set = add_pipe(p, 'p1', 'j1', 'j2', 10.0, 10.0, 10.0, 10.0, PIPE_STATUS_CLOSED)
+        assert len(change_set.added) == 0
+
+        add_junction(p, 'j1', 0.0, 0.0, 0.0)
+        add_junction(p, 'j2', 10.0, 10.0, 0.0)
+        add_junction(p, 'j3', 0.0, 0.0, 0.0)
+        add_junction(p, 'j4', 10.0, 10.0, 0.0)
+        assert is_junction(p, 'j1')
+        assert is_junction(p, 'j2')
+        assert is_junction(p, 'j3')
+        assert is_junction(p, 'j4')
+
+        assert not is_link(p, 'p1')
+
+        change_set = add_pipe(p, 'p1', 'j1', 'j2', 10.0, 10.0, 10.0, 10.0, "XXX")
+        assert len(change_set.added) == 0
+
+        change_set = add_pipe(p, 'p1', 'j1', 'j1', 10.0, 10.0, 10.0, 10.0, PIPE_STATUS_CLOSED)
+        assert len(change_set.added) == 0
+
+        change_set = add_pipe(p, 'p1', 'j1', 'j2', 10.0, 10.0, 10.0, 10.0, PIPE_STATUS_CLOSED)
+        assert len(change_set.added) == 1
+        assert change_set.added[0]['type'] == PIPE
+        assert change_set.added[0]['id'] == "p1"
+
+        change_set = add_pipe(p, 'p1', 'j1', 'j2', 10.0, 10.0, 10.0, 10.0, PIPE_STATUS_CLOSED)
+        assert len(change_set.added) == 0
+
+        pipes = get_links(p)
+        assert len(pipes) == 1
+
+        assert get_pipe_node1(p, 'p1') == 'j1'
+        assert get_pipe_node2(p, 'p1') == 'j2'
+        assert get_pipe_length(p, 'p1') == 10.0
+        assert get_pipe_diameter(p, 'p1') == 10.0
+        assert get_pipe_roughness(p, 'p1') == 10.0
+        assert get_pipe_minor_loss(p, 'p1') == 10.0
+        assert get_pipe_status(p, 'p1') == PIPE_STATUS_CLOSED
+
+        change_set = set_pipe_node1(p, 'p1', 'j2')
+        assert len(change_set.updated) == 0
+        change_set = set_pipe_node2(p, 'p1', 'j1')
+        assert len(change_set.updated) == 0
+        change_set = set_pipe_status(p, 'p1', "XXX")
+        assert len(change_set.updated) == 0
+
+        change_set = set_pipe_node1(p, 'p1', 'j3')
+        assert len(change_set.updated) == 1
+        assert change_set.updated[0]['type'] == PIPE
+        assert change_set.updated[0]['id'] == 'p1'
+        assert change_set.updated[0]['property'] == 'node1'
+
+        change_set = set_pipe_node2(p, 'p1', 'j4')
+        assert len(change_set.updated) == 1
+        assert change_set.updated[0]['type'] == PIPE
+        assert change_set.updated[0]['id'] == 'p1'
+        assert change_set.updated[0]['property'] == 'node2'
+
+        change_set = set_pipe_length(p, 'p1', 100.0)
+        assert len(change_set.updated) == 1
+        assert change_set.updated[0]['type'] == PIPE
+        assert change_set.updated[0]['id'] == 'p1'
+        assert change_set.updated[0]['property'] == 'length'
+
+        change_set = set_pipe_diameter(p, 'p1', 100.0)
+        assert len(change_set.updated) == 1
+        assert change_set.updated[0]['type'] == PIPE
+        assert change_set.updated[0]['id'] == 'p1'
+        assert change_set.updated[0]['property'] == 'diameter'
+
+        change_set = set_pipe_roughness(p, 'p1', 100.0)
+        assert len(change_set.updated) == 1
+        assert change_set.updated[0]['type'] == PIPE
+        assert change_set.updated[0]['id'] == 'p1'
+        assert change_set.updated[0]['property'] == 'roughness'
+
+        change_set = set_pipe_minor_loss(p, 'p1', 100.0)
+        assert len(change_set.updated) == 1
+        assert change_set.updated[0]['type'] == PIPE
+        assert change_set.updated[0]['id'] == 'p1'
+        assert change_set.updated[0]['property'] == 'minor_loss'
+
+        change_set = set_pipe_status(p, 'p1', PIPE_STATUS_OPEN)
+        assert len(change_set.updated) == 1
+        assert change_set.updated[0]['type'] == PIPE
+        assert change_set.updated[0]['id'] == 'p1'
+        assert change_set.updated[0]['property'] == 'status'
+
+        assert get_pipe_node1(p, 'p1') == 'j3'
+        assert get_pipe_node2(p, 'p1') == 'j4'
+        assert get_pipe_length(p, 'p1') == 100.0
+        assert get_pipe_diameter(p, 'p1') == 100.0
+        assert get_pipe_roughness(p, 'p1') == 100.0
+        assert get_pipe_minor_loss(p, 'p1') == 100.0
+        assert get_pipe_status(p, 'p1') == PIPE_STATUS_OPEN
+
+        change_set = add_pipe(p, 'p2', 'j1', 'j2', 10.0, 10.0, 10.0, 10.0, PIPE_STATUS_CLOSED)
+        assert len(change_set.added) == 1
+        assert change_set.added[0]['type'] == PIPE
+        assert change_set.added[0]['id'] == "p2"
+
+        pipes = get_links(p)
+        assert len(pipes) == 2
+
+        change_set = delete_pipe(p, 'p')
+        assert len(change_set.deleted) == 0
+
+        assert is_pipe(p, 'p1')
+
+        change_set = delete_pipe(p, 'p1')
+        assert len(change_set.deleted) == 1
+        assert change_set.deleted[0]['type'] == PIPE
+        assert change_set.deleted[0]['id'] == "p1"
+
+        pipes = get_links(p)
+        assert len(pipes) == 1
+
+        change_set = delete_pipe(p, 'p2')
+        assert len(change_set.deleted) == 1
+        assert change_set.deleted[0]['type'] == PIPE
+        assert change_set.deleted[0]['id'] == "p2"
+
+        self.leave(p)
 
     def test_pump(self):
         pass