Add HW 3

homework/03-http-server/tests/env_gen.go

@@ -0,0 +1,73 @@
+package hw3test
+
+import "math/rand"
+
+// EnvGen contains config for generating test environment.
+// Test environment is a directory with files and subdirectories.
+type EnvGen struct {
+	// Generated file tree will not contain subdirectories deeper than this depth.
+	MaxDepth int
+	// Generated file tree will not contain more than this number of subdirs.
+	MaxDirs int
+	// Generated file tree will not contain more than this number of files.
+	MaxFiles int
+	// Generated files will be text files.
+	TextOnly bool
+	// Maximum file size in KB
+	MaxFileSizeKB int
+	// TempDirectory will contain subdirectory for every new environment.
+	TempDirectory string
+	// SparseUnusedFiles avoids writing initial file contents that no query can read.
+	SparseUnusedFiles bool
+	// Allow to use env for configuration.
+	AllowEnv bool
+	// Filename generator.
+	FilenameGen func(r *rand.Rand) string
+}
+
+// GenerateFile returns file with random contents.
+func (g *EnvGen) GenerateFile(r *rand.Rand) *EnvFile {
+	return &EnvFile{
+		GenSeed:  r.Int63(),
+		Size:     r.Int63n(1024 * int64(g.MaxFileSizeKB)),
+		TextOnly: g.TextOnly,
+	}
+}
+
+// Generate generates whole file tree.
+func (g *EnvGen) Generate(seed int64) (*Env, error) {
+	r := rand.New(rand.NewSource(seed))
+	root := &EnvDir{Listing: map[string]EnvNode{}}
+
+	dirs := []*EnvDir{root}
+
+	for i := 0; i < g.MaxDirs; i++ {
+		parent := dirs[r.Intn(len(dirs))]
+		if parent.Depth >= g.MaxDepth {
+			continue
+		}
+
+		name := g.FilenameGen(r)
+		newDir, exist := parent.CreateDir(name)
+		if exist {
+			continue
+		}
+		dirs = append(dirs, newDir)
+	}
+
+	for i := 0; i < g.MaxFiles; i++ {
+		parent := dirs[r.Intn(len(dirs))]
+
+		name := g.FilenameGen(r)
+		_, exist := parent.Listing[name]
+		if exist {
+			continue
+		}
+
+		parent.Listing[name] = g.GenerateFile(r)
+	}
+
+	return &Env{
+		RootDir: root,
+	}, nil
+}