add memoryfs vfs implementation

1 files changed, 70 insertions, 0 deletions

diff --git a/internal/vfs/memoryfs_test.go b/internal/vfs/memoryfs_test.go
new file mode 100644
index 0000000..46607e0
--- /dev/null
+++ b/internal/vfs/memoryfs_test.go
@@ -0,0 +1,70 @@
+package vfs
+
+import (
+	"slices"
+	"strings"
+	"testing"
+)
+
+func TestMemoryFS(t *testing.T) {
+	t.Parallel()
+	var vfs VFS = make(MemoryFS)
+
+	writeFiles := map[string]string{
+		"/data/dir/foo.json":        "hello world",
+		"/data/dir/subdir/bar.json": "hello solar system",
+		"/data/dir/subdir/baz.json": "hello universe",
+		"/data/dir/subdir/bay.txt":  "hello bar keeper",
+	}
+
+	for path, content := range writeFiles {
+		bytes := []byte(content)
+		_ = vfs.WriteFile(path, bytes)
+	}
+
+	t.Run("files are there", func(t *testing.T) {
+		testFilesAreThere(t, vfs, writeFiles)
+	})
+
+	t.Run("find json files", func(t *testing.T) {
+		testFindFiles(t, vfs, writeFiles, "/data/dir/subdir", ".json", 2)
+	})
+}
+
+func testFindFiles(t *testing.T, vfs VFS, writeFiles map[string]string, dataDir, suffix string, count int) {
+	filePaths, err := vfs.FindFiles(dataDir, suffix)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	if len(filePaths) != count {
+		t.Error("expected", count, "json files, but got", filePaths)
+		return
+	}
+
+	for filePath := range writeFiles {
+		if !strings.HasPrefix(filePath, dataDir) || !strings.HasSuffix(filePath, suffix) {
+			continue
+		}
+
+		if !slices.Contains(filePaths, filePath) {
+			t.Error("expected file", filePath, "to be there, but it isn't in", filePaths)
+			return
+		}
+	}
+}
+
+func testFilesAreThere(t *testing.T, vfs VFS, writeFiles map[string]string) {
+	for path, content := range writeFiles {
+		bytes, err := vfs.ReadFile(path)
+		if err != nil {
+			t.Error(err)
+			return
+		}
+		if content != string(bytes) {
+			t.Error("expected", content, "in file", path, "but got", string(bytes))
+			return
+		}
+	}
+}