feat: Tests for bind mounts (#66)

Issue #, if available:

*Description of changes:*
Test functioning of nested bind mounts with and without $DOCKER_COMAPT
set.

1. Without $FINCH_DOCKER_COMAPT.
```
# fails when nested directories are mounted first followed by parent directory
finch finch run -it  -v /Users/siravara/outer/nest/://Users/siravara/outer/nest/ -v  /Users/siravara/temp_home/:/Users/siravara/outer  public.ecr.aws/amazonlinux/amazonlinux:2 sh -c "ls /Users/siravara/outer/nest/"

# passes when parent directory is mounted first followed by nested directories
finch finch run -it  -v  /Users/siravara/temp_home/:/Users/siravara/outer -v /Users/siravara/outer/nest/://Users/siravara/outer/nest/  public.ecr.aws/amazonlinux/amazonlinux:2 sh -c "ls /Users/siravara/outer/nest/"

```

2. With $FINCH_DOCKER_COMAT set

```
# passes when nested directories are mounted first followed by parent directory
finch finch run -it  -v /Users/siravara/outer/nest/://Users/siravara/outer/nest/ -v  /Users/siravara/temp_home/:/Users/siravara/outer  public.ecr.aws/amazonlinux/amazonlinux:2 sh -c "ls /Users/siravara/outer/nest/"

# passes when parent directory is mounted first followed by nested directories
finch finch run -it  -v  /Users/siravara/temp_home/:/Users/siravara/outer -v /Users/siravara/outer/nest/://Users/siravara/outer/nest/  public.ecr.aws/amazonlinux/amazonlinux:2 sh -c "ls /Users/siravara/outer/nest/"
```
*Testing done:*
Yes locally. 


- [X] I've reviewed the guidance in CONTRIBUTING.md


#### License Acceptance

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license.

---------

Signed-off-by: Vishwas Siravara <[email protected]>

fenv/get.go

@@ -0,0 +1,15 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+// Package fenv Package path implements utility routines for working with environment variables
+package fenv
+
+import (
+	"os"
+)
+
+// GetEnv retrieves the value of an environment variable.
+// It returns an empty string if the variable is not set.
+func GetEnv(key string) string {
+	return os.Getenv(key)
+}

ffs/create.go

@@ -60,3 +60,20 @@ func CreateTempDir(directoryPrefix string) string {
 	gomega.Expect(err).ShouldNot(gomega.HaveOccurred())
 	return tempDir
 }
+
+// CreateNestedDir creates a nested directory and returns the path of the created directory.
+// It is the caller's responsibility to remove the directory when it is no longer needed.
+func CreateNestedDir(dirPath string) string {
+	homeDir, err := os.UserHomeDir()
+	gomega.Expect(err).ShouldNot(gomega.HaveOccurred())
+	fullPath := filepath.Join(homeDir, dirPath)
+	err = os.MkdirAll(fullPath, 0o740)
+	gomega.Expect(err).ShouldNot(gomega.HaveOccurred())
+	return fullPath
+}
+
+// DeleteDirectory deletes the directory including nested directories.
+func DeleteDirectory(directoryPath string) {
+	err := os.RemoveAll(directoryPath)
+	gomega.Expect(err).ShouldNot(gomega.HaveOccurred())
+}

tests/run.go

@@ -16,6 +16,7 @@ import (
 	"github.com/onsi/ginkgo/v2"
 	"github.com/onsi/gomega"
 	"github.com/onsi/gomega/gbytes"
+	"github.com/runfinch/common-tests/fenv"
 
 	"github.com/runfinch/common-tests/command"
 	"github.com/runfinch/common-tests/ffs"
@@ -446,6 +447,81 @@ func Run(o *RunOption) {
 				verifyMountsInfo(actualMount, expectedMount)
 			})
 
+			// TODO: Remove FINCH_DOCKER_COMPAT=1 check when FINCH_DOCKER_COMPAT flag is removed in finch
+			ginkgo.It("should create nested bind mounts within a container when FINCH_DOCKER_COMPAT is not set", func() {
+				const (
+					outerDir  = "/outer"
+					nestedDir = "/outer/nested"
+				)
+
+				if fenv.GetEnv("FINCH_DOCKER_COMPAT") == "1" {
+					ginkgo.Skip("Skipping test: FINCH_DOCKER_COMPAT is set to 1")
+				}
+				// Create the nested directory on the host
+				hostDirectory := ffs.CreateNestedDir(outerDir)
+				nestedDirectory := ffs.CreateNestedDir(nestedDir)
+				defer ffs.DeleteDirectory(hostDirectory)
+
+				// Directory on host to be mounted at hostDirectory in container
+				tempDir := ffs.CreateTempDir("some_dir")
+				defer ffs.DeleteDirectory(tempDir)
+				// Write a file to the nested directory
+				nestedFilePath := filepath.Join(nestedDirectory, "file1.txt")
+				ffs.WriteFile(nestedFilePath, "test")
+
+				// Mount nested directory first followed by parent directory
+				// Upstream issue: https://github.com/containerd/nerdctl/issues/2254
+				command.RunWithoutSuccessfulExit(o.BaseOpt, "run", "--rm", "--name", testContainerName,
+					"-v", nestedDirectory+":"+nestedDirectory,
+					"-v", tempDir+":"+hostDirectory,
+					defaultImage, "sh", "-c", "ls "+nestedDirectory)
+
+				// Mount parent directory first followed by nested
+				output := command.StdoutStr(o.BaseOpt, "run", "--rm", "--name", testContainerName2,
+					"-v", tempDir+":"+hostDirectory,
+					"-v", nestedDirectory+":"+nestedDirectory,
+					defaultImage, "sh", "-c", "ls "+nestedDirectory)
+				gomega.Expect(output).Should(gomega.ContainSubstring("file1.txt"))
+			})
+
+			// TODO: Remove FINCH_DOCKER_COMPAT=1 check when FINCH_DOCKER_COMPAT flag is removed in finch
+			// https://github.com/runfinch/finch/pull/417/files
+
+			ginkgo.It("should create nested bind mounts within a container when FINCH_DOCKER_COMPAT is set", func() {
+				const (
+					outerDir  = "/outer"
+					nestedDir = "/outer/nested"
+				)
+				if fenv.GetEnv("FINCH_DOCKER_COMPAT") != "1" {
+					ginkgo.Skip("Skipping test: FINCH_DOCKER_COMPAT is not set to 1")
+				}
+				// Create the nested directory on the host
+				hostDirectory := ffs.CreateNestedDir(outerDir)
+				nestedDirectory := ffs.CreateNestedDir(nestedDir)
+				defer ffs.DeleteDirectory(hostDirectory)
+
+				// Directory on host to be mounted at hostDirectory in container
+				tempDir := ffs.CreateTempDir("some_dir")
+				defer ffs.DeleteDirectory(tempDir)
+				// Write a file to the nested directory
+				nestedFilePath := filepath.Join(nestedDirectory, "file1.txt")
+				ffs.WriteFile(nestedFilePath, "test")
+
+				// Mount nested directory first followed by parent directory
+				output := command.StdoutStr(o.BaseOpt, "run", "--rm", "--name", testContainerName,
+					"-v", nestedDirectory+":"+nestedDirectory,
+					"-v", tempDir+":"+hostDirectory,
+					defaultImage, "sh", "-c", "ls "+nestedDirectory)
+				gomega.Expect(output).Should(gomega.ContainSubstring("file1.txt"))
+
+				// Mount parent directory first followed by nested
+				output = command.StdoutStr(o.BaseOpt, "run", "--rm", "--name", testContainerName2,
+					"-v", tempDir+":"+hostDirectory,
+					"-v", nestedDirectory+":"+nestedDirectory,
+					defaultImage, "sh", "-c", "ls "+nestedDirectory)
+				gomega.Expect(output).Should(gomega.ContainSubstring("file1.txt"))
+			})
+
 			ginkgo.It("should create a tmpfs mount using --mount type=tmpfs flag", func() {
 				tmpfsDir := "/tmpfsDir"
 				command.Run(o.BaseOpt, "run", "-d", "--name", testContainerName, "--mount",