Added readme

Signed-off-by: Janos <[email protected]>

README.md

@@ -20,4 +20,29 @@ func TestMyApplication(t *testing.T) {
 
 	your.App(ctx)
 }
-```
+```
+
+## Randomness
+
+The random functions provide a number of randomness sources for testing purposes, some deterministic, some not.
+
+To obtain a deterministic randomness source *tied to a test name*, you can use the `DeterministicSource` (implementing an `io.Reader`) as follows:
+
+```go
+package your_test
+
+import (
+	"testing"
+	"your"
+
+	"github.com/opentofu/tofutestutils"
+)
+
+func TestMyApp(t *testing.T) {
+	randomness := tofutestutils.DeterministicRandomSource(t)
+
+    your.App(randomness)	
+}
+```
+
+For a full list of possible functions, please [check the Go docs](https://pkg.go.dev/github.com/opentofu/tofutestutils).

testrandom/README.md

@@ -0,0 +1,24 @@
+# Randomness sources
+
+This folder contains a number of randomness sources for testing purposes, some deterministic, some not.
+
+To obtain a deterministic randomness source *tied to a test name*, you can use the `DeterministicSource` (implementing an `io.Reader`) as follows:
+
+```go
+package your_test
+
+import (
+	"testing"
+	"your"
+
+	"github.com/opentofu/tofutestutils/testrandom"
+)
+
+func TestMyApp(t *testing.T) {
+	randomness := testrandom.DeterministicSource(t)
+
+    your.App(randomness)	
+}
+```
+
+For a full list of possible functions, please [check the Go docs](https://pkg.go.dev/github.com/opentofu/tofutestutils/testrandom).