From 6d59744bd5ada23bec3df3b69ee2fada5158cf30 Mon Sep 17 00:00:00 2001
From: RealZogger <49367953+RealZogger@users.noreply.github.com>
Date: Tue, 14 Jan 2020 21:49:27 +0000
Subject: [PATCH 1/2] Support negative indices in getCall

This allows getting calls indexed from the end of the array
e.g. -1 gets the last call, -2 gets the penultimate call etc.
---
 docs/release-source/release/spies.md |  2 ++
 lib/sinon/proxy.js                   |  6 +++-
 test/spy-test.js                     | 42 ++++++++++++++++++++++++++++
 3 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/docs/release-source/release/spies.md b/docs/release-source/release/spies.md
index b77f40fc2..be8a9b995 100644
--- a/docs/release-source/release/spies.md
+++ b/docs/release-source/release/spies.md
@@ -350,6 +350,8 @@ Returns `true` if spy always returned the provided value.
 
 Returns the *nth* [call](#spycall).
 
+If *n* is negative, the *nth* call from the end is returned. For example, `spy.getCall(-1)` returns the last call, and `spy.getCall(-2)` returns the second to last call.
+
 Accessing individual calls helps with more detailed behavior verification when the spy is called more than once.
 
 <div data-example-id="spies-8-spy-call"></div>
diff --git a/lib/sinon/proxy.js b/lib/sinon/proxy.js
index 7af3fb788..28e7e86d3 100644
--- a/lib/sinon/proxy.js
+++ b/lib/sinon/proxy.js
@@ -40,7 +40,11 @@ var proxyApi = {
         return emptyFakes;
     },
 
-    getCall: function getCall(i) {
+    getCall: function getCall(index) {
+        var i = index;
+        if (i < 0) {
+            i += this.callCount;
+        }
         if (i < 0 || i >= this.callCount) {
             return null;
         }
diff --git a/test/spy-test.js b/test/spy-test.js
index 5c35d9d4d..3bbf50bab 100644
--- a/test/spy-test.js
+++ b/test/spy-test.js
@@ -2086,6 +2086,48 @@ describe("spy", function() {
         });
     });
 
+    describe(".getCall", function() {
+        it("is null for indexes >= length", function() {
+            var spy = createSpy();
+
+            spy();
+
+            assert.isNull(spy.getCall(1));
+            assert.isNull(spy.getCall(2));
+        });
+
+        it("is null for indexes < -length", function() {
+            var spy = createSpy();
+
+            spy();
+
+            assert.isNull(spy.getCall(-2));
+            assert.isNull(spy.getCall(-3));
+        });
+
+        it("is same as last call when passed index -1", function() {
+            var spy = createSpy();
+
+            spy();
+            spy();
+            spy();
+
+            assert.same(spy.getCall(-1).callId, spy.lastCall.callId);
+            assert.same(spy.getCall(-1).spy, spy.lastCall.spy);
+        });
+
+        it("is same as n-1th call when passed index -2", function() {
+            var spy = createSpy();
+
+            spy();
+            spy();
+            spy();
+
+            assert.same(spy.getCall(-2).callId, spy.getCall(1).callId);
+            assert.same(spy.getCall(-2).spy, spy.getCall(1).spy);
+        });
+    });
+
     describe(".lastCall", function() {
         it("is undefined by default", function() {
             var spy = createSpy();

From d851a5ed367faadb97a410a017f14097f986e277 Mon Sep 17 00:00:00 2001
From: RealZogger <49367953+RealZogger@users.noreply.github.com>
Date: Wed, 15 Jan 2020 22:17:14 +0000
Subject: [PATCH 2/2] Add clarifying comment for negative indices

---
 lib/sinon/proxy.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/sinon/proxy.js b/lib/sinon/proxy.js
index 28e7e86d3..7b7807aad 100644
--- a/lib/sinon/proxy.js
+++ b/lib/sinon/proxy.js
@@ -43,6 +43,7 @@ var proxyApi = {
     getCall: function getCall(index) {
         var i = index;
         if (i < 0) {
+            // Negative indices means counting backwards from the last call
             i += this.callCount;
         }
         if (i < 0 || i >= this.callCount) {