feat: add message endpoint, implement e2e test

.eslintrc.json

@@ -13,7 +13,11 @@
     {
       "files": ["*.test.js", "*.spec.js"],
       "rules": {
-        "no-unused-expressions": "off"
+        "no-unused-expressions": "off",
+        "no-console": [
+          "warn",
+          { "allow": ["clear", "info", "error", "dir", "trace", "log"] }
+         ]
       }
     }
   ],

__tests__/e2e/message.spec.js

@@ -0,0 +1,95 @@
+const uuid = require('uuid');
+const { pgClient, pgClient2 } = require('../../server/infra/database/pgClient');
+
+// test to confrim successful clients' subscription to a postgres channel
+describe('subscribes clients to postgres channel "new_tree_notification" and adds new tree record to confirm subscription', () => {
+    afterAll((done) => { // eslint-disable-line
+        pgClient.end();
+        pgClient2.end();
+        done();
+    })
+
+    // creates two clients and confirms their subscription to a postgres channel
+    it('subscribes two cilents', (done) => {
+
+        //  tree object to be added to table
+        const messageObj = {
+            name: 'tree',
+            data: {
+                capture_id: uuid.v4()
+            }
+        }
+
+        // query to create notification function on postgres schema
+        pgClient.query(`CREATE OR REPLACE FUNCTION queue.new_message_notify_trigger() RETURNS TRIGGER AS $$
+            DECLARE
+            BEGIN
+                CASE NEW.name
+                    WHEN 'tree' THEN
+                        PERFORM pg_notify(cast('tree_notification' as text), row_to_json(new)::text);
+                        RETURN NEW;
+                    WHEN 'planter' THEN
+                        PERFORM pg_notify(cast('planter_notification' as text), row_to_json(new)::text);
+                        RETURN NEW;
+                    ELSE
+                        RETURN NEW;
+                END CASE;
+            END;
+            $$ LANGUAGE plpgsql;`
+            , (err, res) => {
+                if (err) throw Error(`function creation error: ${err}`)
+                console.log("function created: ", res);
+            });
+
+        // query to create trigger on postgres table
+        pgClient.query(`DROP TRIGGER IF EXISTS new_message_insert_trigger on queue.message`, (err) => {
+            if (err) throw Error(`trigger drop error: ${err}`);
+        })
+        pgClient.query(`CREATE TRIGGER new_message_insert_trigger BEFORE INSERT ON queue.message
+            FOR EACH ROW EXECUTE PROCEDURE queue.new_message_notify_trigger();`, (err, res) => {
+            if (err) throw Error(`trigger creation error: ${err}`);
+            console.log("trigger created: ", res);
+        });
+
+        // create promises to receive notifications and verify message/payload
+        Promise.all([
+            new Promise((resolve) => {
+                pgClient.on('notification', msg => {
+                    const newRow = JSON.parse(msg.payload);
+                    return resolve(newRow);
+                });
+            }),
+            new Promise((resolve) => {
+                pgClient2.on('notification', msg => {
+                    const newRow = JSON.parse(msg.payload);
+                    return resolve(newRow);
+                });
+            })
+        ]).then(values => {
+            expect(values[0]).toMatchObject(messageObj); // eslint-disable-line
+            expect(values[1]).toMatchObject(messageObj); // eslint-disable-line
+            done();
+        });
+
+        // subscribe clients to a postgres channel
+        pgClient.query(`LISTEN tree_notification`, (err, res) => {
+            if (err) throw Error(`subscription error: ${err}`);
+            console.log("listen notification success: ", res);
+        });
+
+        pgClient2.query(`LISTEN tree_notification`, (err, res) => {
+            if (err) throw Error(`subscription error: ${err}`);
+            console.log("listen notification success: ", res);
+        });
+
+        // insert new row to postgres table, serves same function as sending a message
+        const text = `INSERT into queue.message(name, data) values ($1, $2) RETURNING *`;
+        const values = [messageObj.name, messageObj.data];
+
+        pgClient.query(text, values, (err, res) => {
+            if (err) throw Error(`insertion error: ${err}`);
+            console.log("postgres row insertion success: ", res);
+        });
+
+    }, 30000)
+})