Dismount tool prior to deletion

app/mutations/tools/destroy.rb

@@ -1,8 +1,8 @@
 module Tools
   class Destroy < Mutations::Command
-    STILL_IN_USE  = "Can't delete tool because the following sequences are "\
-                    "still using it: %s"
-    STILL_IN_SLOT = "Can't delete tool because it is still in a tool slot. "\
+    STILL_IN_USE = "Can't delete tool because the following sequences are " \
+                   "still using it: %s"
+    STILL_IN_SLOT = "Can't delete tool because it is still in a tool slot. " \
                     "Please remove it from the tool slot first."
 
     required do
@@ -15,10 +15,11 @@ module Tools
     end
 
     def execute
+      maybe_unmount_tool
       tool.destroy!
     end
 
-private
+    private
 
     def slot
       @slot ||= tool.tool_slot
@@ -33,8 +34,14 @@ private
     end
 
     def names
-      @names ||= \
+      @names ||=
         InUseTool.where(tool_id: tool.id).pluck(:sequence_name).join(", ")
     end
+
+    def maybe_unmount_tool
+      if tool.device.mounted_tool_id == tool.id
+        tool.device.update!(mounted_tool_id: nil)
+      end
+    end
   end
 end

spec/controllers/api/tools/destroy_spec.rb

@@ -1,17 +1,18 @@
-require 'spec_helper'
+require "spec_helper"
 
 describe Api::ToolsController do
   include Devise::Test::ControllerHelpers
-  describe '#destroy' do
+  describe "#destroy" do
     let(:user) { FactoryBot.create(:user) }
     let(:tool_slot) { FactoryBot.create(:tool_slot) }
     let!(:tool) {
-        Point.destroy_all
-        FactoryBot.create(:tool,
-                           tool_slot: tool_slot,
-                           device: user.device) }
+      Point.destroy_all
+      FactoryBot.create(:tool,
+                        tool_slot: tool_slot,
+                        device: user.device)
+    }
 
-    it 'destroy a tool' do
+    it "destroy a tool" do
       sign_in user
       before = Tool.count
       tool.tool_slot.update(tool: nil)
@@ -21,24 +22,23 @@ describe Api::ToolsController do
       expect(before).to be > after
     end
 
-    it 'does not destroy a tool when in use by a sequence' do
+    it "does not destroy a tool when in use by a sequence" do
       PinBinding.destroy_all
       Sequence.destroy_all
-      Sequences::Create.run!(name:   "Dep. tracking",
+      Sequences::Create.run!(name: "Dep. tracking",
                              device: user.device,
-                             body:   [
-                              {
-                                kind: "move_absolute",
-                                args: {
-                                    location: { kind: "tool", args: { tool_id: tool.id }
-                                    },
-                                    offset: { kind: "coordinate", args: {x: 1, y: 2, z: 3} },
-                                    speed: 100
-                                }
-                              }
-                            ])
+                             body: [
+                               {
+                                 kind: "move_absolute",
+                                 args: {
+                                   location: { kind: "tool", args: { tool_id: tool.id } },
+                                   offset: { kind: "coordinate", args: { x: 1, y: 2, z: 3 } },
+                                   speed: 100,
+                                 },
+                               },
+                             ])
       sequence = Sequence.last
-      sd_list  = EdgeNode
+      sd_list = EdgeNode
         .where(kind: "tool_id", sequence: sequence)
         .map { |x| Tool.find(x.value) }
       sign_in user
@@ -52,11 +52,21 @@ describe Api::ToolsController do
 
       expect(response.status).to eq(422)
       expect(before).to eq(after)
-      expect(json[:tool])
-        .to include(Tools::Destroy::STILL_IN_USE % sequence.name)
+      expect(json[:tool]).to include(Tools::Destroy::STILL_IN_USE % sequence.name)
     end
 
-    it 'does not destroy a tool when in a slot' do
+    it "dismounts a tool when it is deleted" do
+      sign_in user
+      before = Tool.count
+      tool.tool_slot.update(tool: nil)
+      tool.device.update!(mounted_tool_id: tool.id)
+      delete :destroy, params: { id: tool.id }
+      after = Tool.count
+      expect(response.status).to eq(200)
+      expect(before).to be > after
+    end
+
+    it "does not destroy a tool when in a slot" do
       sign_in user
       before = Tool.count
       delete :destroy, params: { id: tool.id }