add UpdateWithEnv func

os/env.go

@@ -0,0 +1,15 @@
+package osutils
+
+import (
+ "os"
+ "strings"
+)
+
+// UpdateWithEnv replaces a string variable with its corresponding environment variable value.
+// If the environment variable does not exist, it remains unchanged.
+func UpdateWithEnv(variable *string) {
+ if variable == nil {
+ return
+ }
+ *variable = os.Getenv(strings.TrimPrefix(*variable, "$"))
+}

os/env_test.go

@@ -0,0 +1,44 @@
+package osutils
+
+import (
+ "os"
+ "testing"
+)
+
+func TestUpdateWithEnv(t *testing.T) {
+ testEnvVar := "TEST_VAR"
+ testEnvValue := "TestValue"
+ os.Setenv(testEnvVar, testEnvValue)
+ defer os.Unsetenv(testEnvVar)
+
+ tests := []struct {
+ input string
+ expected string
+ name string
+ }{
+ {"$" + testEnvVar, testEnvValue, "Existing env variable"},
+ {"$NON_EXISTENT_VAR", "", "Non-existent env variable"},
+ {"NOT_AN_ENV_VAR", "", "Not prefixed with $"},
+ {"", "", "Empty string"},
+ }
+
+ for _, tt := range tests {
+ t.Run(tt.name, func(t *testing.T) {
+ UpdateWithEnv(&tt.input)
+ if tt.input != tt.expected {
+ t.Errorf("got %q, want %q", tt.input, tt.expected)
+ }
+ })
+ }
+}
+
+func TestUpdateWithEnvNilInput(t *testing.T) {
+ defer func() {
+ if r := recover(); r != nil {
+ t.Errorf("The code panicked with %v", r)
+ }
+ }()
+
+ var nilVar *string = nil
+ UpdateWithEnv(nilVar)
+}