Chore: Adding additional test for pull request #3945 (#4078)

**Summary**
Adding an additional test for an uncovered method from pull request #3945. The previous tests did not cover this, since the method, `getExactVersionMatch`, is only called if a package's `fresh` prop is false or the frozen flag is set. The fixtures directory for this test contains a lockfile to meet this condition.

If the `manifest && getExoticResolver(version)` condition does not evaluate properly the `multiplePackagesCantUnpackInSameDestination` warning is logged. This test checks for that.

**Test plan**

New tests, obviously :)

Author: Jack Aldridge

__tests__/commands/install/integration.js

@@ -491,6 +491,19 @@ test.concurrent('install file: dedupe dependencies 2', (): Promise<void> => {
   });
 });
 
+// When local packages are installed from a repo with a lockfile, the multiple packages
+// unpacking in the same location warning should not occur
+test.concurrent('install file: dedupe dependencies 3', (): Promise<void> => {
+  return runInstall({}, 'install-file-dedupe-dependencies-3', (config, reporter, install, getStdout) => {
+    const stdout = getStdout();
+    // Need to check if message is logged, but don't need to check for any specific parameters
+    // so splitting on undefined and testing if all message parts are in stdout
+    const messageParts = reporter.lang('multiplePackagesCantUnpackInSameDestination').split('undefined');
+    const warningMessage = messageParts.every(part => stdout.includes(part));
+    expect(warningMessage).toBe(false);
+  });
+});
+
 test.concurrent('install everything when flat is enabled', (): Promise<void> => {
   return runInstall({noLockfile: true, flat: true}, 'install-file', async config => {
     expect(await fs.readFile(path.join(config.cwd, 'node_modules', 'foo', 'index.js'))).toEqual('foobar;\n');

__tests__/fixtures/install/install-file-dedupe-dependencies-3/a/package.json

@@ -0,0 +1,7 @@
+{
+  "name": "a",
+  "version": "1.0.0",
+  "dependencies": {
+    "b": "file:../b"
+  }
+}

__tests__/fixtures/install/install-file-dedupe-dependencies-3/b/package.json

@@ -0,0 +1,4 @@
+{
+  "name": "b",
+  "version": "1.0.0"
+}

__tests__/fixtures/install/install-file-dedupe-dependencies-3/package.json

@@ -0,0 +1,6 @@
+{
+  "dependencies": {
+    "a": "file:a",
+    "b": "file:./b"
+  }
+}

__tests__/fixtures/install/install-file-dedupe-dependencies-3/yarn.lock

@@ -0,0 +1,11 @@
+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+
+
+"a@file:a":
+  version "1.0.0"
+  dependencies:
+    b "file:../b"
+
+"b@file:./b", "b@file:b":
+  version "1.0.0"