diff --git a/pkg/docker/docker_test.go b/pkg/docker/docker_test.go
new file mode 100644
index 0000000..d0bee05
--- /dev/null
+++ b/pkg/docker/docker_test.go
@@ -0,0 +1,144 @@
+package docker
+
+import (
+	"testing"
+)
+
+func TestIsValidEnvVarKey(t *testing.T) {
+	testCases := []struct {
+		name     string
+		key      string
+		expected bool
+	}{
+		{
+			name:     "Empty string",
+			key:      "",
+			expected: false,
+		},
+		{
+			name:     "Single letter",
+			key:      "A",
+			expected: true,
+		},
+		{
+			name:     "Single underscore",
+			key:      "_",
+			expected: true,
+		},
+		{
+			name:     "Letter and digit",
+			key:      "MY_VAR1",
+			expected: true,
+		},
+		{
+			name:     "Letter, digit, and underscore",
+			key:      "MY_VAR_123",
+			expected: true,
+		},
+		{
+			name:     "Starting with digit",
+			key:      "123_MY_VAR",
+			expected: false,
+		},
+		{
+			name:     "Invalid character",
+			key:      "MY_VAR@",
+			expected: false,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			result := isValidEnvVarKey(tc.key)
+			if result != tc.expected {
+				t.Errorf("Expected %v for key %q, but got %v", tc.expected, tc.key, result)
+			}
+		})
+	}
+}
+
+func TestIsLetter(t *testing.T) {
+	testCases := []struct {
+		name     string
+		r        rune
+		expected bool
+	}{
+		{
+			name:     "Uppercase letter",
+			r:        'A',
+			expected: true,
+		},
+		{
+			name:     "Lowercase letter",
+			r:        'a',
+			expected: true,
+		},
+		{
+			name:     "Underscore",
+			r:        '_',
+			expected: true,
+		},
+		{
+			name:     "Digit",
+			r:        '1',
+			expected: false,
+		},
+		{
+			name:     "Special character",
+			r:        '@',
+			expected: false,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			result := isLetter(tc.r)
+			if result != tc.expected {
+				t.Errorf("Expected %v for rune %q, but got %v", tc.expected, string(tc.r), result)
+			}
+		})
+	}
+}
+
+func TestIsLetterOrDigitOrUnderscore(t *testing.T) {
+	testCases := []struct {
+		name     string
+		r        rune
+		expected bool
+	}{
+		{
+			name:     "Uppercase letter",
+			r:        'A',
+			expected: true,
+		},
+		{
+			name:     "Lowercase letter",
+			r:        'a',
+			expected: true,
+		},
+		{
+			name:     "Underscore",
+			r:        '_',
+			expected: true,
+		},
+		{
+			name:     "Digit",
+			r:        '1',
+			expected: true,
+		},
+		{
+			name:     "Special character",
+			r:        '@',
+			expected: false,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			result := isLetterOrDigitOrUnderscore(tc.r)
+			if result != tc.expected {
+				t.Errorf("Expected %v for rune %q, but got %v", tc.expected, string(tc.r), result)
+			}
+		})
+	}
+}
diff --git a/pkg/generate/generate_enigma_test.go b/pkg/generate/generate_enigma_test.go
new file mode 100644
index 0000000..c385207
--- /dev/null
+++ b/pkg/generate/generate_enigma_test.go
@@ -0,0 +1,63 @@
+package generate
+
+import (
+	"bufio"
+	"os"
+	"testing"
+)
+
+func TestGenerateEnigmaFile(t *testing.T) {
+	// Create a temporary file for testing
+	tempFile, err := os.CreateTemp("", "enigma_test_*.env")
+	if err != nil {
+		t.Fatalf("Failed to create temporary file: %v", err)
+	}
+	defer os.Remove(tempFile.Name())
+	tempFile.Close()
+
+	// Test case for DOCKER environment type
+	t.Run("DOCKER environment", func(t *testing.T) {
+		err := GenerateEnigmaFile(tempFile.Name(), DOCKER)
+		if err != nil {
+			t.Fatalf("GenerateEnigmaFile failed: %v", err)
+		}
+
+		// Read the content of the generated file
+		file, err := os.Open(tempFile.Name())
+		if err != nil {
+			t.Fatalf("Failed to open generated file: %v", err)
+		}
+		defer file.Close()
+
+		scanner := bufio.NewScanner(file)
+		lineCount := 0
+		for scanner.Scan() {
+			line := scanner.Text()
+			if lineCount >= len(DOCKER_ENV_VARIABLES) {
+				t.Errorf("Too many lines in the generated file")
+				break
+			}
+			expectedLine := DOCKER_ENV_VARIABLES[lineCount]
+			if line != expectedLine {
+				t.Errorf("Line %d: expected %q, got %q", lineCount+1, expectedLine, line)
+			}
+			lineCount++
+		}
+
+		if err := scanner.Err(); err != nil {
+			t.Fatalf("Error reading generated file: %v", err)
+		}
+
+		if lineCount != len(DOCKER_ENV_VARIABLES) {
+			t.Errorf("Expected %d lines, got %d", len(DOCKER_ENV_VARIABLES), lineCount)
+		}
+	})
+
+	// Test case for invalid file path
+	t.Run("Invalid file path", func(t *testing.T) {
+		err := GenerateEnigmaFile("/invalid/path/file.env", DOCKER)
+		if err == nil {
+			t.Error("Expected an error for invalid file path, but got nil")
+		}
+	})
+}