Add test of deterministic and non deterministic provider's methods

src/main/java/net/datafaker/annotations/Deterministic.java

@@ -0,0 +1,12 @@
+package net.datafaker.annotations;
+
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.METHOD)
+public @interface Deterministic {
+}

src/main/java/net/datafaker/providers/base/Address.java

@@ -1,5 +1,7 @@
 package net.datafaker.providers.base;
 
+import net.datafaker.annotations.Deterministic;
+
 /**
  * @since 0.8.0
  */
@@ -67,6 +69,7 @@ public String streetSuffix() {
         return resolve("address.street_suffix");
     }
 
+    @Deterministic
     public String streetPrefix() {
         return resolve("address.street_prefix");
     }

src/main/java/net/datafaker/providers/base/Drone.java

@@ -1,5 +1,7 @@
 package net.datafaker.providers.base;
 
+import net.datafaker.annotations.Deterministic;
+
 /**
  * An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board.
  *
@@ -107,6 +109,7 @@ public String minShutterSpeed() {
         return resolve("drone.min_shutter_speed");
     }
 
+    @Deterministic
     public String shutterSpeedUnits() {
         return resolve("drone.shutter_speed_units");
     }

src/main/java/net/datafaker/providers/base/Locality.java

@@ -1,5 +1,7 @@
 package net.datafaker.providers.base;
 
+import net.datafaker.annotations.Deterministic;
+
 import java.io.File;
 import java.io.IOException;
 import java.lang.management.ManagementFactory;
@@ -42,6 +44,7 @@ public Locality(BaseProviders baseProviders) {
      *
      * @return a List of Strings with the name of the locale (eg. "es", "es-MX")
      */
+    @Deterministic
     public List<String> allSupportedLocales() {
         return allSupportedLocales(Set.of("datafaker"));
     }

src/main/java/net/datafaker/providers/base/Mbti.java

@@ -1,41 +1,43 @@
 package net.datafaker.providers.base;
 
+import java.util.function.Supplier;
+
 /**
  * Myers-Briggs Type Indicator
  *
  * @since 1.5.0
  */
 public class Mbti extends AbstractProvider<BaseProviders> {
 
-    private final String choice;
+    private final Supplier<String> choice;
 
     public Mbti(final BaseProviders faker) {
         super(faker);
-        this.choice = this.faker.resolve("mbti.choice");
+        this.choice = () -> this.faker.resolve("mbti.choice");
     }
 
     public String type() {
-        return resolve("mbti.".concat(choice).concat(".type"));
+        return resolve("mbti.".concat(choice.get()).concat(".type"));
     }
 
     public String name() {
-        return resolve("mbti.".concat(choice).concat(".name"));
+        return resolve("mbti.".concat(choice.get()).concat(".name"));
     }
 
     public String characteristic() {
-        return resolve("mbti.".concat(choice).concat(".characteristic"));
+        return resolve("mbti.".concat(choice.get()).concat(".characteristic"));
     }
 
     public String personage() {
-        return resolve("mbti.".concat(choice).concat(".personage"));
+        return resolve("mbti.".concat(choice.get()).concat(".personage"));
     }
 
     public String merit() {
-        return resolve("mbti.".concat(choice).concat(".merit"));
+        return resolve("mbti.".concat(choice.get()).concat(".merit"));
     }
 
     public String weakness() {
-        return resolve("mbti.".concat(choice).concat(".weakness"));
+        return resolve("mbti.".concat(choice.get()).concat(".weakness"));
     }
 
 

src/test/java/net/datafaker/FakerTest.java

@@ -1,18 +1,31 @@
 package net.datafaker;
 
+import net.datafaker.annotations.Deterministic;
+import net.datafaker.providers.base.AbstractProvider;
 import net.datafaker.providers.base.BaseFaker;
 import org.junit.jupiter.api.RepeatedTest;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
-
+import org.reflections.Reflections;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashSet;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Random;
+import java.util.Set;
 import java.util.concurrent.Callable;
+import java.util.stream.Collectors;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.reflections.scanners.Scanners.SubTypes;
 
 class FakerTest extends AbstractFakerTest {
 
@@ -348,4 +361,57 @@ void shouldNotApplyCachingToMethodsWithParameters() {
         String flight2 = faker.expression("#{Aviation.flight 'ICAO'}");
         assertThat(flight2).matches("[A-z]{3}\\d{1,4}");
     }
+
+    @Test
+    void testDeterministicAndNonDeterministicProvidersReturnValues() {
+        final Reflections reflections = new Reflections("net.datafaker.providers");
+        Set<Class<?>> classes = reflections.get(SubTypes.of(AbstractProvider.class).asClass());
+        for (var clazz: classes) {
+            Collection<Method> methods = Arrays.stream(clazz.getDeclaredMethods())
+                .filter(m -> Modifier.isPublic(m.getModifiers()) && m.getParameterCount() == 0).collect(Collectors.toSet());
+            if (methods.isEmpty()) continue;
+            Constructor<AbstractProvider<?>> constructor = null;
+            final AbstractProvider<?> ap;
+            try {
+                Set<Constructor<AbstractProvider<?>>> constructorsWith1Arg =
+                    Arrays.stream(clazz.getDeclaredConstructors())
+                        .filter(c -> c.getParameterCount() == 1).map(c -> (Constructor<AbstractProvider<?>>) c)
+                        .collect(Collectors.toSet());
+                for (var c: constructorsWith1Arg) {
+                     Class<?>[] types = c.getParameterTypes();
+                     if (types[0].isAssignableFrom(Faker.class)) {
+                         constructor = c;
+                         break;
+                     }
+                 }
+                 assertThat(constructor).isNotNull();
+                 constructor.setAccessible(true);
+                 ap = constructor.newInstance(faker);
+            } catch (InvocationTargetException | InstantiationException |
+                     IllegalAccessException e) {
+                throw new RuntimeException(e);
+            }
+            for (Method m: methods) {
+                var set = new HashSet<>();
+                try {
+                    for (int i = 0; i < 10; i++) {
+                        set.add(m.invoke(ap));
+                    }
+                } catch (IllegalAccessException | InvocationTargetException e) {
+                    throw new RuntimeException(e);
+                }
+                if (m.isAnnotationPresent(Deterministic.class)) {
+                    assertThat(set)
+                        .as("Class: " + ap.getClass().getName()
+                            + ", method: " + m.getName() + " should have the same return value")
+                        .hasSize(1);
+                } else {
+                    assertThat(set)
+                        .as("Class: " + ap.getClass().getName()
+                            + ", method: " + m.getName() + " should generate different return values")
+                        .hasSizeGreaterThan(1);
+                }
+            }
+        }
+    }
 }

src/test/java/net/datafaker/providers/entertainment/OscarMovieTest.java

@@ -1,14 +1,7 @@
 package net.datafaker.providers.entertainment;
 
 import org.junit.jupiter.api.RepeatedTest;
-import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.MethodSource;
 
-import java.util.Collection;
-import java.util.List;
-import java.util.function.Function;
-import java.util.stream.Collectors;
-import java.util.stream.Stream;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.util.Strings.isNullOrEmpty;
@@ -42,28 +35,4 @@ void releaseDate() {
         assertThat(oscarMovie.releaseDate()).matches("[A-Za-z,0-9 ]+");
     }
 
-    /**
-     * Test for <a href="https://github.com/datafaker-net/datafaker/issues/741">issue741</a>
-     */
-    @ParameterizedTest
-    @MethodSource("argsProvider")
-    void issue741(Function<OscarMovie, String> f) {
-        final OscarMovie oscarMovie = faker.oscarMovie();
-        assertThat(
-            faker.stream(() -> f.apply(oscarMovie)).len(10).build()
-                .<Stream<?>>get().collect(Collectors.toSet()))
-            .hasSizeGreaterThan(1);
-    }
-
-    static Collection<Function<OscarMovie, String>> argsProvider() {
-        return List.of(
-            OscarMovie::actor,
-            OscarMovie::character,
-            OscarMovie::getChoice,
-            OscarMovie::getYear,
-            OscarMovie::movieName,
-            OscarMovie::quote,
-            OscarMovie::releaseDate
-        );
-    }
 }