From 27081adae2dbb18da945d7109742b2cbeff64b9b Mon Sep 17 00:00:00 2001
From: Nuno Cruces <ncruces@users.noreply.github.com>
Date: Fri, 10 Feb 2023 17:14:43 +0000
Subject: [PATCH] Tests.

---
 vfs_lock_test.go | 58 +++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 50 insertions(+), 8 deletions(-)

diff --git a/vfs_lock_test.go b/vfs_lock_test.go
index e2b296e..f2b2740 100644
--- a/vfs_lock_test.go
+++ b/vfs_lock_test.go
@@ -8,6 +8,7 @@ import (
 )
 
 func Test_vfsLock(t *testing.T) {
+	// Other OSes lack open file descriptors locks.
 	switch runtime.GOOS {
 	case "linux", "darwin", "solaris", "windows":
 		//
@@ -15,6 +16,7 @@ func Test_vfsLock(t *testing.T) {
 		t.Skip()
 	}
 
+	// Create a temporary file.
 	file1, err := os.CreateTemp("", "sqlite3-")
 	if err != nil {
 		t.Fatal(err)
@@ -24,12 +26,14 @@ func Test_vfsLock(t *testing.T) {
 	name := file1.Name()
 	defer os.RemoveAll(name)
 
+	// Open the temporary file again.
 	file2, err := os.OpenFile(name, os.O_RDWR, 0)
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer file2.Close()
 
+	// Bypass open file reuse.
 	vfsOpenFiles = append(vfsOpenFiles, &vfsOpenFile{
 		file:   file1,
 		nref:   1,
@@ -44,37 +48,75 @@ func Test_vfsLock(t *testing.T) {
 	mem.writeUint32(4+4, 0)
 	mem.writeUint32(16+4, 1)
 
-	rc := vfsCheckReservedLock(context.TODO(), mem.mod, 4, 32)
+	const (
+		pFile1  = 4
+		pFile2  = 16
+		pOutput = 32
+	)
+
+	rc := vfsCheckReservedLock(context.TODO(), mem.mod, pFile1, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(16); got != 0 {
+	if got := mem.readUint32(pOutput); got != 0 {
 		t.Error("file was locked")
 	}
 
-	rc = vfsLock(context.TODO(), mem.mod, 16, _SHARED_LOCK)
+	rc = vfsLock(context.TODO(), mem.mod, pFile2, _SHARED_LOCK)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
 
-	rc = vfsCheckReservedLock(context.TODO(), mem.mod, 4, 32)
+	rc = vfsCheckReservedLock(context.TODO(), mem.mod, pFile1, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(32); got != 0 {
+	if got := mem.readUint32(pOutput); got != 0 {
 		t.Error("file was locked")
 	}
 
-	rc = vfsLock(context.TODO(), mem.mod, 16, _RESERVED_LOCK)
+	rc = vfsLock(context.TODO(), mem.mod, pFile2, _RESERVED_LOCK)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	rc = vfsLock(context.TODO(), mem.mod, pFile2, _SHARED_LOCK)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
 
-	rc = vfsCheckReservedLock(context.TODO(), mem.mod, 4, 32)
+	rc = vfsCheckReservedLock(context.TODO(), mem.mod, pFile1, pOutput)
 	if rc != _OK {
 		t.Fatal("returned", rc)
 	}
-	if got := mem.readUint32(32); got == 0 {
+	if got := mem.readUint32(pOutput); got == 0 {
 		t.Error("file wasn't locked")
 	}
+
+	rc = vfsLock(context.TODO(), mem.mod, pFile2, _EXCLUSIVE_LOCK)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+
+	rc = vfsCheckReservedLock(context.TODO(), mem.mod, pFile1, pOutput)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+	if got := mem.readUint32(pOutput); got == 0 {
+		t.Error("file wasn't locked")
+	}
+
+	rc = vfsLock(context.TODO(), mem.mod, pFile1, _SHARED_LOCK)
+	if rc == _OK {
+		t.Fatal("returned", rc)
+	}
+
+	rc = vfsUnlock(context.TODO(), mem.mod, pFile2, _SHARED_LOCK)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
+
+	rc = vfsLock(context.TODO(), mem.mod, pFile1, _SHARED_LOCK)
+	if rc != _OK {
+		t.Fatal("returned", rc)
+	}
 }