diff --git a/cli/Valet/PhpFpm.php b/cli/Valet/PhpFpm.php
index 385b6ee..b065c92 100644
--- a/cli/Valet/PhpFpm.php
+++ b/cli/Valet/PhpFpm.php
@@ -137,6 +137,7 @@ function stopRunning()
      * Use a specific version of php
      *
      * @param $version
+     * @return string
      */
     function useVersion($version)
     {
@@ -147,18 +148,18 @@ function useVersion($version)
 
         info(sprintf('Finding brew formula for: %s', $version));
         $foundVersion = $this->brew->search($version)
-            ->filter(function ($service) {
+            ->first(function ($service) {
                 return $this->brew->supportedPhpVersions()->contains($service);
-            })
-            ->first();
-        info(sprintf('Found brew formula: %s', $foundVersion));
+            });
 
-        if (!$this->brew->supportedPhpVersions()->contains($foundVersion)) {
+        if (is_null($foundVersion)) {
             throw new DomainException(
-                sprintf('Valet doesn\'t support PHP version: %s', $foundVersion)
+                sprintf('Valet can\'t find a supported version of PHP for: %s', $version)
             );
         }
 
+        info(sprintf('Found brew formula: %s', $foundVersion));
+
         if ($this->brew->hasLinkedPhp()) {
             $currentVersion = $this->brew->linkedPhp();
             info(sprintf('Unlinking current version: %s', $currentVersion));
@@ -171,5 +172,7 @@ function useVersion($version)
         $this->brew->link($foundVersion, true);
 
         $this->install();
+
+        return $foundVersion;
     }
 }
diff --git a/cli/valet.php b/cli/valet.php
index b3c4455..2f04166 100755
--- a/cli/valet.php
+++ b/cli/valet.php
@@ -282,10 +282,10 @@
     $app->command('use phpVersion', function ($phpVersion) {
         PhpFpm::stopRunning();
 
-        PhpFpm::useVersion($phpVersion);
+        $newVersion = PhpFpm::useVersion($phpVersion);
 
         Nginx::restart();
-        info(sprintf('Valet is now using %s.', $phpVersion));
+        info(sprintf('Valet is now using %s.', $newVersion));
     })->descriptions('Change the version of php used by valet', [
         'phpVersion' => 'The PHP version you want to use, e.g php@7.2',
     ]);
diff --git a/tests/PhpFpmTest.php b/tests/PhpFpmTest.php
index 4169cfa..c8d675a 100644
--- a/tests/PhpFpmTest.php
+++ b/tests/PhpFpmTest.php
@@ -2,6 +2,8 @@
 
 use Valet\Brew;
 use Valet\PhpFpm;
+use Valet\Filesystem;
+use Valet\CommandLine;
 use function Valet\user;
 use function Valet\swap;
 use function Valet\resolve;
@@ -61,13 +63,79 @@ public function test_stopRunning_will_pass_filtered_result_of_getRunningServices
         resolve(PhpFpm::class)->stopRunning();
     }
 
-    // TODO: useVersion if no php at start it will prefix
-    // TODO: useVersion will pass version to Brew::search and then check if it's supported
-    // TODO:     - if not supported will through
-    // TODO: useVersion if already linked php will unlink it
-    // TODO: useVersion will ensure new version is installed
-    // TODO: useVersion will link found version (force)
-    // TODO: useVersion will call install at end
+    public function test_use_version_if_no_php_at_start_will_prefix()
+    {
+        $brewMock = Mockery::mock(Brew::class);
+        $phpFpmMock = Mockery::mock(PhpFpm::class, [
+            $brewMock,
+            resolve(CommandLine::class),
+            resolve(Filesystem::class),
+        ])->makePartial();
+
+        $phpFpmMock->shouldReceive('install');
+
+        $brewMock->shouldReceive('search')->with('php7.2')->twice()->andReturn(collect([
+            'php@7.2'
+        ]));
+        $brewMock->shouldReceive('supportedPhpVersions')->twice()->andReturn(collect([
+            'php@7.2',
+            'php@5.6',
+        ]));
+        $brewMock->shouldReceive('hasLinkedPhp')->andReturn(False);
+        $brewMock->shouldReceive('ensureInstalled')->with('php@7.2');
+        $brewMock->shouldReceive('link')->withArgs(['php@7.2', true]);
+
+        // Test both non prefixed and prefixed
+        $this->assertSame('php@7.2', $phpFpmMock->useVersion('7.2'));
+        $this->assertSame('php@7.2', $phpFpmMock->useVersion('php7.2'));
+    }
+
+    /**
+     * @expectedException DomainException
+     * @expectedExceptionMessage Valet can't find a supported version of PHP for: php7.2
+     */
+    public function test_use_version_will_throw_if_searched_version_is_not_supported()
+    {
+        $brewMock = Mockery::mock(Brew::class);
+        swap(Brew::class, $brewMock);
+
+        $brewMock->shouldReceive('search')->with('php7.2')->andReturn(collect([
+            'php@7.2'
+        ]));
+        $brewMock->shouldReceive('supportedPhpVersions')->andReturn(collect([
+            'php@7.3',
+            'php@7.1',
+        ]));
+
+        resolve(PhpFpm::class)->useVersion('7.2');
+    }
+
+    public function test_use_version_if_already_linked_php_will_unlink_before_installing()
+    {
+        $brewMock = Mockery::mock(Brew::class);
+        $phpFpmMock = Mockery::mock(PhpFpm::class, [
+            $brewMock,
+            resolve(CommandLine::class),
+            resolve(Filesystem::class),
+        ])->makePartial();
+        $phpFpmMock->shouldReceive('install');
+
+        $brewMock->shouldReceive('search')->with('php@7.2')->andReturn(collect([
+            'php@7.2'
+        ]));
+        $brewMock->shouldReceive('supportedPhpVersions')->andReturn(collect([
+            'php@7.2',
+            'php@5.6',
+        ]));
+        $brewMock->shouldReceive('hasLinkedPhp')->andReturn(true);
+        $brewMock->shouldReceive('linkedPhp')->andReturn('php@7.1');
+        $brewMock->shouldReceive('unlink')->with('php@7.1');
+        $brewMock->shouldReceive('ensureInstalled')->with('php@7.2');
+        $brewMock->shouldReceive('link')->withArgs(['php@7.2', true]);
+
+        // Test both non prefixed and prefixed
+        $this->assertSame('php@7.2', $phpFpmMock->useVersion('php@7.2'));
+    }
 }