test: confirm finding by a relation with a composite key works (#8052)

Co-authored-by: vlastv <me@vlastv.ru>

test/functional/query-builder/composite-primary/composite-primary.ts

@@ -0,0 +1,37 @@
+import "reflect-metadata";
+import {closeTestingConnections, createTestingConnections, reloadTestingDatabases} from "../../../utils/test-utils";
+import {Connection} from "../../../../src";
+import {Foo} from "./entity/Foo";
+import {Bar} from "./entity/Bar";
+import {expect} from "chai";
+
+describe("query builder > composite primary", () => {
+
+    let connections: Connection[];
+    before(async () => connections = await createTestingConnections({
+        entities: [ Foo, Bar ],
+        enabledDrivers: ["postgres"]
+    }));
+    beforeEach(() => reloadTestingDatabases(connections));
+    after(() => closeTestingConnections(connections));
+
+    it("should find entity by another entity with a composite key", () => Promise.all(connections.map(async connection => {
+        const foo = new Foo();
+        foo.id1 = 1
+        foo.id2 = 2;
+        await connection.manager.save(foo)
+
+        const bar = new Bar()
+        bar.id = 1
+        bar.foo = foo
+        await connection.manager.save(bar)
+
+        const loadedBar = await connection.manager.getRepository(Bar).findOne({
+            where: {
+                foo
+            }
+        });
+
+        expect(loadedBar!.id).to.be.equal(bar.id);
+    })));
+});

test/functional/query-builder/composite-primary/entity/Bar.ts

@@ -0,0 +1,13 @@
+import {Entity} from "../../../../../src/decorator/entity/Entity";
+import { ManyToOne, PrimaryColumn } from "../../../../../src";
+import { Foo } from "./Foo";
+
+@Entity()
+export class Bar {
+
+    @PrimaryColumn()
+    id: number;
+
+    @ManyToOne(type => Foo)
+    foo: Foo
+}

test/functional/query-builder/composite-primary/entity/Foo.ts

@@ -0,0 +1,12 @@
+import {Entity} from "../../../../../src/decorator/entity/Entity";
+import { PrimaryColumn } from "../../../../../src";
+
+@Entity()
+export class Foo {
+
+    @PrimaryColumn()
+    id1: number;
+
+    @PrimaryColumn()
+    id2: number;
+}