Add Environment.Delete (#243)

Co-authored-by: Victor Gaydov <victor@enise.org>

Author: nhAnik

environment.go

@@ -61,6 +61,20 @@ func (e *Environment) Put(key string, value interface{}) {
 	e.data[key] = value
 }
 
+// Delete removes the value with key from the environment.
+//
+// Example:
+//
+//	env := NewEnvironment(t)
+//	env.Put("key1", "str")
+//	env.Delete("key1")
+func (e *Environment) Delete(key string) {
+	opChain := e.chain.enter("Delete(%q)", key)
+	defer opChain.leave()
+
+	delete(e.data, key)
+}
+
 // Has returns true if value exists in the environment.
 //
 // Example:

environment_test.go

@@ -53,6 +53,26 @@ func TestEnvironment_Generic(t *testing.T) {
 	env.chain.assertFailed(t)
 }
 
+func TestEnvironment_Delete(t *testing.T) {
+	env := newEnvironment(newMockChain(t))
+
+	env.Put("good_key", 123)
+	env.chain.assertNotFailed(t)
+
+	assert.True(t, env.Has("good_key"))
+	assert.NotNil(t, env.Get("good_key"))
+	assert.Equal(t, 123, env.Get("good_key").(int))
+	env.chain.assertNotFailed(t)
+
+	env.Delete("good_key")
+	env.chain.assertNotFailed(t)
+
+	assert.False(t, env.Has("good_key"))
+	assert.Nil(t, env.Get("good_key"))
+	env.chain.assertFailed(t)
+	env.chain.clearFailed()
+}
+
 func TestEnvironment_NotFound(t *testing.T) {
 	env := newEnvironment(newMockChain(t))