Refactor CardAccountRangeService to Flow-based interface for improved testability #12206

toluo-stripe · 2026-01-07T23:34:20Z

Summary

This is a structural change to make the card funding work simpler (especially from a testing perspective).

This PR refactors CardAccountRangeService from a concrete callback-based implementation to an interface-based architecture with Kotlin Flow reactivity:

Architectural Changes:

Extract CardAccountRangeService interface with DefaultCardAccountRangeService implementation
Replace callback-based AccountRangeResultListener with reactive Flows
Migrate to constructor injection pattern across CardNumberEditText and CardNumberController

Test Infrastructure:

Create FakeCardAccountRangeService for easier test injection
Modernize tests with Turbine library, replacing CountDownLatch/CompletableDeferred with flow.test { awaitItem() } patterns
Update test assertions to use flow collection instead of callback verification

Integration Updates:

Move service initialization from lazy properties to constructor parameters in CardNumberEditText and CardNumberController
Update call sites to collect flows for type-safe result handling

Motivation

The existing CardAccountRangeService implementation uses a concrete class with callback-based state updates, making it difficult to test components that depend on it. This refactoring:

Enables testability: Interface-based design allows easy substitution with fakes in tests, critical for upcoming card funding feature development
Modernizes reactive patterns: Flows provide better composability and lifecycle awareness compared to callbacks
Improves separation of concerns: Clear interface contract makes dependencies explicit through constructor injection
Prepares for card funding work: Both DefaultCardNumberController and AccountRangeService will be modified for card funding features - this structural foundation makes those changes safer and easier to test

Testing

Added tests
Modified tests
Manually verified

Changelog

github-actions · 2026-01-07T23:40:30Z

Diffuse output:

OLD: paymentsheet-example-release-master.apk (signature: V1, V2)
NEW: paymentsheet-example-release-pr.apk (signature: V1, V2)

          │              compressed              │           uncompressed           
          ├─────────────┬─────────────┬──────────┼───────────┬───────────┬──────────
 APK      │ old         │ new         │ diff     │ old       │ new       │ diff     
──────────┼─────────────┼─────────────┼──────────┼───────────┼───────────┼──────────
      dex │     4.9 MiB │     4.9 MiB │ -2.4 KiB │    11 MiB │    11 MiB │ -1.2 KiB 
     arsc │     3.6 MiB │     3.6 MiB │      0 B │   3.6 MiB │   3.6 MiB │      0 B 
 manifest │     5.7 KiB │     5.7 KiB │      0 B │  30.2 KiB │  30.2 KiB │      0 B 
      res │ 1,002.9 KiB │ 1,002.9 KiB │      0 B │   1.7 MiB │   1.7 MiB │      0 B 
   native │   949.9 KiB │   949.9 KiB │      0 B │   2.5 MiB │   2.5 MiB │      0 B 
    asset │    26.2 KiB │    24.8 KiB │ -1.4 KiB │  46.7 KiB │  45.3 KiB │ -1.4 KiB 
    other │   205.3 KiB │   205.3 KiB │     -2 B │ 405.6 KiB │ 405.6 KiB │      0 B 
──────────┼─────────────┼─────────────┼──────────┼───────────┼───────────┼──────────
    total │    10.6 MiB │    10.6 MiB │ -3.8 KiB │  19.1 MiB │  19.1 MiB │ -2.7 KiB 

         │         raw          │              unique               
         ├───────┬───────┬──────┼───────┬───────┬───────────────────
 DEX     │ old   │ new   │ diff │ old   │ new   │ diff              
─────────┼───────┼───────┼──────┼───────┼───────┼───────────────────
   files │     2 │     2 │    0 │       │       │                   
 strings │ 58698 │ 58618 │  -80 │ 52145 │ 52152 │  +7 (+26 -19)     
   types │ 20714 │ 20656 │  -58 │ 17443 │ 17449 │  +6 (+22 -16)     
 classes │ 14675 │ 14681 │   +6 │ 14675 │ 14681 │  +6 (+10 -4)      
 methods │ 78294 │ 78243 │  -51 │ 73261 │ 73276 │ +15 (+1380 -1365) 
  fields │ 51282 │ 51261 │  -21 │ 48934 │ 48943 │  +9 (+881 -872)   

 ARSC    │ old  │ new  │ diff 
─────────┼──────┼──────┼──────
 configs │  325 │  325 │  0   
 entries │ 6941 │ 6941 │  0

APK

      compressed      │     uncompressed     │                                
───────────┬──────────┼───────────┬──────────┤                                
 size      │ diff     │ size      │ diff     │ path                           
───────────┼──────────┼───────────┼──────────┼────────────────────────────────
 810.6 KiB │ -5.9 KiB │   1.8 MiB │ -9.8 KiB │ ∆ classes2.dex                 
   4.1 MiB │ +3.5 KiB │   9.2 MiB │ +8.6 KiB │ ∆ classes.dex                  
   8.4 KiB │ -1.4 KiB │   8.3 KiB │ -1.4 KiB │ ∆ assets/dexopt/baseline.prof  
  54.4 KiB │     -6 B │ 127.2 KiB │      0 B │ ∆ META-INF/MANIFEST.MF         
  57.6 KiB │     +4 B │ 127.3 KiB │      0 B │ ∆ META-INF/CERT.SF             
   1.2 KiB │     -1 B │     1 KiB │     -1 B │ ∆ assets/dexopt/baseline.profm 
───────────┼──────────┼───────────┼──────────┼────────────────────────────────
     5 MiB │ -3.8 KiB │  11.2 MiB │ -2.7 KiB │ (total)

DEX

STRINGS:

   old   │ new   │ diff         
  ───────┼───────┼──────────────
   52145 │ 52152 │ +7 (+26 -19) 
  
  + , unfilteredAccountRanges=
  + Lme/k;
  + Ln5/a0;
  + Lt9/l;
  + Lvh/r;
  + Lwd/h;
  + Lzb/v;
  + Lzb/w;
  + Lzb/x;
  + Success(accountRanges=
  + [Lkh/a0;
  + [Lkh/e;
  + [Lkh/p;
  + [Ln5/i;
  + [Ln5/o;
  + [Lzh/h0;
  + [Lzh/n0;
  + [Lzh/u0;
  + r8-map-id-57b7a0efeab5317b720b00440ade19354d77ee8cd31403fdeca7c553622e3f24
  + ~~R8{"backend":"dex","compilation-mode":"release","has-checksums":false,"min-api":21,"pg-map-id":"57b7a0efeab5317b720b00440ade19354d77ee8cd31403fdeca7c553622e3f24","r8-mode":"full","version":"8.13.17"}
  + Lhl/n1;
  + Lhl/o1;
  + [Lhl/c1;
  + [Lhl/d0;
  + [Lhl/l0;
  + [Lhl/m1;
  
  - Lmc/l;
  - Lt5/g0;
  - Lvb/e;
  - Lwe/j;
  - [Lkh/b0;
  - [Lkh/g;
  - [Lkh/q;
  - [Ln5/h;
  - [Ln5/n;
  - [Lzh/i0;
  - [Lzh/p0;
  - [Lzh/w0;
  - r8-map-id-59cdc766c776da1a075e84c30b5c3034467ac2e8578323bc13404cd8b09fbe39
  - ~~R8{"backend":"dex","compilation-mode":"release","has-checksums":false,"min-api":21,"pg-map-id":"59cdc766c776da1a075e84c30b5c3034467ac2e8578323bc13404cd8b09fbe39","r8-mode":"full","version":"8.13.17"}
  - [Lhl/j0;
  - [Lhl/k1;
  - [Lhl/y0;
  - [Lhl/y;
  - getAccountRangeService_annotations
  

TYPES:

   old   │ new   │ diff         
  ───────┼───────┼──────────────
   17443 │ 17449 │ +6 (+22 -16) 
  
  + Lme/k;
  + Ln5/a0;
  + Lt9/l;
  + Lvh/r;
  + Lwd/h;
  + Lzb/v;
  + Lzb/w;
  + Lzb/x;
  + [Lkh/a0;
  + [Lkh/e;
  + [Lkh/p;
  + [Ln5/i;
  + [Ln5/o;
  + [Lzh/h0;
  + [Lzh/n0;
  + [Lzh/u0;
  + Lhl/n1;
  + Lhl/o1;
  + [Lhl/c1;
  + [Lhl/d0;
  + [Lhl/l0;
  + [Lhl/m1;
  
  - Lmc/l;
  - Lt5/g0;
  - Lvb/e;
  - Lwe/j;
  - [Lkh/b0;
  - [Lkh/g;
  - [Lkh/q;
  - [Ln5/h;
  - [Ln5/n;
  - [Lzh/i0;
  - [Lzh/p0;
  - [Lzh/w0;
  - [Lhl/j0;
  - [Lhl/k1;
  - [Lhl/y0;
  - [Lhl/y;
  

METHODS:

   old   │ new   │ diff              
  ───────┼───────┼───────────────────
   73261 │ 73276 │ +15 (+1380 -1365) 
  
  + a.a G(k) → b
  + a4.b0 c(View) → boolean
  + a4.j D(WindowInsetsController, c0)
  + a4.j s(View, r1)
  + a4.j v(WindowInsetsController, c0)
  + a4.o e(KProperty, Object)
  + a6.a b(Object, int, int, h) → b0
  + a6.c0 b(Object, int, int, h) → b0
  + a6.c <init>(Resources, b0)
  + a6.d transform(Context, b0, int, int) → b0
  + a6.e b(Object, int, int, h) → b0
  + a6.f0 e(MediaMetadataRetriever, Object)
  + a6.g0 b(Object, int, int, h) → b0
  + a6.s transform(Context, b0, int, int) → b0
  + a6.w J(b0, h) → b0
  + aa.q f(v) → p
  + aa.q g(y) → Typeface
  + ac.y a(d, f, d, f, c) → d
  + ae.e0 <init>(b0, w, j, Continuation)
  + ae.l <init>(s, c)
  + ae.p0 <init>(c, CoroutineContext, CoroutineContext, t, a, c)
  + ae.p0 b() → b
  + ae.p0 c(i, boolean)
  + ae.p0 d(i)
  + ae.p0 e(List)
  + af.n0 d(String, String, boolean, q, Continuation) → Object
  + af.s0 f(v) → p
  + af.s0 g() → IntentFilter
  + af.s0 h(int) → int[]
  + ai.a2 a(h)
  + ai.e2 a(h)
  + ak.f J(b0, h) → b0
  + ak.f c(View) → boolean
  + ak.f d(long) → boolean
  + ak.f e() → k
  + ak.m a() → boolean
  + ak.m b(k, String, int) → n3
  + ak.m c(int)
  + ak.m e(long, q, q, q) → q
  + ak.m f(Context) → int
  + ak.m h(Context, boolean) → int
  + ak.m j(q, q, q) → long
  + ak.m k() → int
  + ak.m l(long, q, q, q) → q
  + ak.m o() → int
  + androidx.appcompat.widget.ActionBarContextView i(int, long) → i1
  + androidx.coordinatorlayout.widget.CoordinatorLayout getLastWindowInsets() → j2
  + b8.b f(Context) → int
  + b8.b h(Context, boolean) → int
  + b8.f m0(p, List) → k
  + bd.i0 f(v) → p
  + bd.i0 g(Object)
  + bd.i0 h(q1)
  + bf.d b(d, d, f, Context, CoroutineContext) → k
  + c6.b b(Object, int, int, h) → b0
  + c6.b c(Uri) → b0
  + ch.a onApplyWindowInsets(View, j2) → j2
  + cj.h <init>(e, i, w, e, Application, b1, h0)
  + com.android.volley.toolbox.f <init>(String, s, ImageView_ScaleType, Bitmap_Config, r)
  + com.android.volley.toolbox.f b(k) → t
  + com.android.volley.toolbox.f getPriority() → o
  + com.android.volley.toolbox.f parseNetworkResponse(k) → t
  + com.android.volley.toolbox.g parseNetworkResponse(k) → t
  + com.android.volley.toolbox.h <init>(String, String, s, r)
  + com.bumptech.glide.b <init>(Context, m, d, a, f, i, e, e, e, List)
  + com.bumptech.glide.c <init>(Context, f, f, i, e, e, List, m)
  + com.google.android.gms.common.internal.a c(g)
  + com.google.android.gms.common.internal.a d(String)
  + com.google.android.gms.common.internal.a e() → boolean
  + com.google.android.gms.common.internal.a g()
  + com.google.android.gms.c
...✂

toluo-stripe · 2026-01-08T00:02:00Z

payments-ui-core/src/test/java/com/stripe/android/ui/core/elements/CardNumberControllerTest.kt

-    @Test
-    fun `Entering VISA BIN does not call accountRangeRepository`() {
-        val fakeRepository = FakeCardAccountRangeRepository()
-        val cardNumberController = createController(repository = fakeRepository)
-
-        cardNumberController.onValueChange("42424242424242424242")
-        idleLooper()
-        assertThat(fakeRepository.numberOfCalls).isEqualTo(0)
-    }
-
-    @Test
-    fun `Entering valid 19 digit UnionPay BIN returns accountRange of 19`() {
-        val cardNumberController = createController()
-        cardNumberController.onValueChange("6216828050000000000")
-        idleLooper()
-        assertThat(cardNumberController.accountRangeService.accountRange!!.panLength).isEqualTo(19)
-    }
-
-    @Test
-    fun `Entering valid 16 digit UnionPay BIN returns accountRange of 16`() {
-        val cardNumberController = createController()
-        cardNumberController.onValueChange("6282000000000000")
-        idleLooper()
-        assertThat(cardNumberController.accountRangeService.accountRange!!.panLength).isEqualTo(16)
-    }


These are testing implementation details of accountRangeService and they already exist in CardAccountRangeServiceTest.kt

toluo-stripe · 2026-01-08T01:25:02Z

payments-core/src/test/java/com/stripe/android/view/CardNumberEditTextTest.kt

-                    assertThat(cardNumberEditText.accountRangeService.accountRangeRepositoryJob)
-                        .isNull()
+                    assertThat(accountRangeService.cancelAccountRangeRepositoryJobCount).isEqualTo(1)
                }


We should not have access to accountRangeRepositoryJob job here

toluo-stripe force-pushed the tolu/funding/structural_changes branch 2 times, most recently from 86efc22 to c55c8ae Compare January 7, 2026 23:58

toluo-stripe changed the title ~~Structural change for CardAccountRangeService~~ Move accountRangeService to DefaultCardNumberController constructor Jan 7, 2026

toluo-stripe commented Jan 8, 2026

View reviewed changes

toluo-stripe force-pushed the tolu/funding/structural_changes branch from c55c8ae to 2450ba3 Compare January 8, 2026 01:20

toluo-stripe commented Jan 8, 2026

View reviewed changes

toluo-stripe force-pushed the tolu/funding/structural_changes branch 4 times, most recently from 0a1071a to aaa1fbf Compare January 8, 2026 14:14

toluo-stripe changed the title ~~Move accountRangeService to DefaultCardNumberController constructor~~ Refactor CardAccountRangeService to Flow-based interface for improved testability Jan 8, 2026

Move accountRangeService to DefaultCardNumberController constructor

f09313d

toluo-stripe force-pushed the tolu/funding/structural_changes branch from aaa1fbf to f09313d Compare January 8, 2026 14:42

toluo-stripe requested a review from jaynewstrom-stripe January 8, 2026 14:42

toluo-stripe marked this pull request as ready for review January 8, 2026 14:42

toluo-stripe requested review from a team as code owners January 8, 2026 14:42

toluo-stripe added 5 commits January 8, 2026 10:07

Fix failing tests

5de5ce4

use unconfined dispatcher

ea9a8bb

no global cardInputListener

17126b5

try to fix tests

a2d674e

Update CardInputWidgetTest.kt

76f5459

toluo-stripe closed this Jan 9, 2026

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Refactor CardAccountRangeService to Flow-based interface for improved testability #12206

Refactor CardAccountRangeService to Flow-based interface for improved testability #12206

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Refactor CardAccountRangeService to Flow-based interface for improved testability #12206

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Summary

Motivation

Testing

Changelog

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