Added Additional Singles Zip Helpers (ReactiveX#124)

* Added Additional Singles Zip Helpers

Added 3->9 sources to match what is available starting here:

https://github.com/ReactiveX/RxJava/blob/2.x/src/main/java/io/reactivex/Single.java#L1113

* Added parameter order tests for Singles Helpers

Author: matwood

src/main/kotlin/io/reactivex/rxkotlin/Singles.kt

@@ -3,12 +3,69 @@ package io.reactivex.rxkotlin
 import io.reactivex.Single
 import io.reactivex.SingleSource
 import io.reactivex.functions.BiFunction
+import io.reactivex.functions.Function3
+import io.reactivex.functions.Function4
+import io.reactivex.functions.Function5
+import io.reactivex.functions.Function6
+import io.reactivex.functions.Function7
+import io.reactivex.functions.Function8
+import io.reactivex.functions.Function9
 
 
 object Singles {
     inline fun <T, U, R> zip(s1: SingleSource<T>, s2: SingleSource<U>, crossinline zipper: (T, U) -> R): Single<R>
-            = Single.zip(s1,s2, BiFunction { t, u -> zipper.invoke(t, u) })
+            = Single.zip(s1, s2, BiFunction { t, u -> zipper.invoke(t, u) })
+    
+    inline fun <T1, T2, T3, R>
+            zip(s1: SingleSource<T1>, s2: SingleSource<T2>, s3: SingleSource<T3>,
+                crossinline zipper: (T1, T2, T3) -> R): Single<R>
+            = Single.zip(s1, s2, s3, Function3 { t1, t2, t3 -> zipper.invoke(t1, t2, t3) })
+
+    inline fun <T1, T2, T3, T4, R>
+            zip(s1: SingleSource<T1>, s2: SingleSource<T2>,
+                s3: SingleSource<T3>, s4: SingleSource<T4>,
+                crossinline zipper: (T1, T2, T3, T4) -> R): Single<R>
+            = Single.zip(s1, s2, s3, s4, Function4 { t1, t2, t3, t4 -> zipper.invoke(t1, t2, t3, t4) })
+
+    inline fun <T1, T2, T3, T4, T5, R>
+            zip(s1: SingleSource<T1>, s2: SingleSource<T2>,
+                s3: SingleSource<T3>, s4: SingleSource<T4>,
+                s5: SingleSource<T5>,
+                crossinline zipper: (T1, T2, T3, T4, T5) -> R): Single<R>
+            = Single.zip(s1, s2, s3, s4, s5, Function5 { t1, t2, t3, t4, t5 -> zipper.invoke(t1, t2, t3, t4, t5) })
+
+    inline fun <T1, T2, T3, T4, T5, T6, R>
+            zip(s1: SingleSource<T1>, s2: SingleSource<T2>,
+                s3: SingleSource<T3>, s4: SingleSource<T4>,
+                s5: SingleSource<T5>, s6: SingleSource<T6>,
+                crossinline zipper: (T1, T2, T3, T4, T5, T6) -> R): Single<R>
+            = Single.zip(s1, s2, s3, s4, s5, s6, Function6 { t1, t2, t3, t4, t5, t6 -> zipper.invoke(t1, t2, t3, t4, t5, t6) })
+
+    inline fun <T1, T2, T3, T4, T5, T6, T7, R>
+            zip(s1: SingleSource<T1>, s2: SingleSource<T2>,
+                s3: SingleSource<T3>, s4: SingleSource<T4>,
+                s5: SingleSource<T5>, s6: SingleSource<T6>,
+                s7: SingleSource<T7>,
+                crossinline zipper: (T1, T2, T3, T4, T5, T6, T7) -> R): Single<R>
+            = Single.zip(s1, s2, s3, s4, s5, s6, s7, Function7 { t1, t2, t3, t4, t5, t6, t7 -> zipper.invoke(t1, t2, t3, t4, t5, t6, t7) })
+
+    inline fun <T1, T2, T3, T4, T5, T6, T7, T8, R>
+            zip(s1: SingleSource<T1>, s2: SingleSource<T2>,
+                s3: SingleSource<T3>, s4: SingleSource<T4>,
+                s5: SingleSource<T5>, s6: SingleSource<T6>,
+                s7: SingleSource<T7>, s8: SingleSource<T8>,
+                crossinline zipper: (T1, T2, T3, T4, T5, T6, T7, T8) -> R): Single<R>
+            = Single.zip(s1, s2, s3, s4, s5, s6, s7, s8, Function8 { t1, t2, t3, t4, t5, t6, t7, t8 -> zipper.invoke(t1, t2, t3, t4, t5, t6, t7, t8) })
+
+    inline fun <T1, T2, T3, T4, T5, T6, T7, T8, T9, R>
+            zip(s1: SingleSource<T1>, s2: SingleSource<T2>,
+                s3: SingleSource<T3>, s4: SingleSource<T4>,
+                s5: SingleSource<T5>, s6: SingleSource<T6>,
+                s7: SingleSource<T7>, s8: SingleSource<T8>,
+                s9: SingleSource<T9>,
+                crossinline zipper: (T1, T2, T3, T4, T5, T6, T7, T8, T9) -> R): Single<R>
+            = Single.zip(s1, s2, s3, s4, s5, s6, s7, s8, s9, Function9 { t1, t2, t3, t4, t5, t6, t7, t8, t9 -> zipper.invoke(t1, t2, t3, t4, t5, t6, t7, t8, t9) })
 }
 
 inline fun <T, U, R> Single<T>.zipWith(other: SingleSource<U>, crossinline zipper: (T, U) -> R): Single<R>
-        = zipWith(other, BiFunction { t, u -> zipper.invoke(t, u) })
+        = zipWith(other, BiFunction { t, u -> zipper.invoke(t, u) })

src/test/kotlin/io/reactivex/rxkotlin/SinglesTest.kt

@@ -0,0 +1,114 @@
+package io.reactivex.rxkotlin
+
+import io.reactivex.Single
+import io.reactivex.SingleSource
+import org.junit.Test
+
+class SinglesTest : KotlinTests() {
+
+    @Test fun testParameterOrder() {
+        Singles.zip(
+                SingleSourceInt(1), SingleSourceInt(2),
+                {one, two ->
+                    assert(one == 1, { -> "Should equal one"})
+                    assert(two == 2, { -> "Should equal two"})
+                }).blockingGet()
+
+        Singles.zip(
+                SingleSourceInt(1), SingleSourceInt(2),
+                SingleSourceInt(3),
+                {one, two, three ->
+                    assert(one == 1, { -> "Should equal one"})
+                    assert(two == 2, { -> "Should equal two"})
+                    assert(three == 3, { -> "Should equal three"})
+                }).blockingGet()
+
+        Singles.zip(
+                SingleSourceInt(1), SingleSourceInt(2),
+                SingleSourceInt(3), SingleSourceInt(4),
+                {one, two, three, four ->
+                    assert(one == 1, { -> "Should equal one"})
+                    assert(two == 2, { -> "Should equal two"})
+                    assert(three == 3, { -> "Should equal three"})
+                    assert(four == 4, { -> "Should equal four"})
+                }).blockingGet()
+
+        Singles.zip(
+                SingleSourceInt(1), SingleSourceInt(2),
+                SingleSourceInt(3), SingleSourceInt(4),
+                SingleSourceInt(5),
+                {one, two, three, four, five ->
+                    assert(one == 1, { -> "Should equal one"})
+                    assert(two == 2, { -> "Should equal two"})
+                    assert(three == 3, { -> "Should equal three"})
+                    assert(four == 4, { -> "Should equal four"})
+                    assert(five == 5, { -> "Should equal five"})
+                }).blockingGet()
+
+        Singles.zip(
+                SingleSourceInt(1), SingleSourceInt(2),
+                SingleSourceInt(3), SingleSourceInt(4),
+                SingleSourceInt(5), SingleSourceInt(6),
+                {one, two, three, four, five, six ->
+                    assert(one == 1, { -> "Should equal one"})
+                    assert(two == 2, { -> "Should equal two"})
+                    assert(three == 3, { -> "Should equal three"})
+                    assert(four == 4, { -> "Should equal four"})
+                    assert(five == 5, { -> "Should equal five"})
+                    assert(six == 6, { -> "Should equal six"})
+                }).blockingGet()
+
+        Singles.zip(
+                SingleSourceInt(1), SingleSourceInt(2),
+                SingleSourceInt(3), SingleSourceInt(4),
+                SingleSourceInt(5), SingleSourceInt(6),
+                SingleSourceInt(7),
+                {one, two, three, four, five, six, seven ->
+                    assert(one == 1, { -> "Should equal one"})
+                    assert(two == 2, { -> "Should equal two"})
+                    assert(three == 3, { -> "Should equal three"})
+                    assert(four == 4, { -> "Should equal four"})
+                    assert(five == 5, { -> "Should equal five"})
+                    assert(six == 6, { -> "Should equal six"})
+                    assert(seven == 7, { -> "Should equal seven"})
+                }).blockingGet()
+
+        Singles.zip(
+                SingleSourceInt(1), SingleSourceInt(2),
+                SingleSourceInt(3), SingleSourceInt(4),
+                SingleSourceInt(5), SingleSourceInt(6),
+                SingleSourceInt(7), SingleSourceInt(8),
+                {one, two, three, four, five, six, seven, eight ->
+                    assert(one == 1, { -> "Should equal one"})
+                    assert(two == 2, { -> "Should equal two"})
+                    assert(three == 3, { -> "Should equal three"})
+                    assert(four == 4, { -> "Should equal four"})
+                    assert(five == 5, { -> "Should equal five"})
+                    assert(six == 6, { -> "Should equal six"})
+                    assert(seven == 7, { -> "Should equal seven"})
+                    assert(eight == 8, { -> "Should equal eight"})
+                }).blockingGet()
+
+        Singles.zip(
+                SingleSourceInt(1), SingleSourceInt(2),
+                SingleSourceInt(3), SingleSourceInt(4),
+                SingleSourceInt(5), SingleSourceInt(6),
+                SingleSourceInt(7), SingleSourceInt(8),
+                SingleSourceInt(9),
+                {one, two, three, four, five, six, seven, eight, nine ->
+                    assert(one == 1, { -> "Should equal one"})
+                    assert(two == 2, { -> "Should equal two"})
+                    assert(three == 3, { -> "Should equal three"})
+                    assert(four == 4, { -> "Should equal four"})
+                    assert(five == 5, { -> "Should equal five"})
+                    assert(six == 6, { -> "Should equal six"})
+                    assert(seven == 7, { -> "Should equal seven"})
+                    assert(eight == 8, { -> "Should equal eight"})
+                    assert(nine == 9, { -> "Should equal nine"})
+                }).blockingGet()
+    }
+}
+
+fun SingleSourceInt(i: Int): SingleSource<Int> {
+    return Single.create({ s -> s.onSuccess(i)})
+}