Fix inverse reset bug

parente · parente · commit 54959dc67780 · 2015-01-25T20:55:03.000-05:00
Post-submission, just for correctness
diff --git a/cachematrix.R b/cachematrix.R
@@ -11,7 +11,7 @@ makeCacheMatrix <- function(x = matrix()) {
     ## cached inverse
     set <- function(y) {
         x <<- y
-        inv <- NULL
+        inv <<- NULL
     }
 
     ## Return the current matrix
diff --git a/test/test_cachematrix.R b/test/test_cachematrix.R
@@ -31,6 +31,19 @@ test_that("makeCacheMatrix(m) sets/gets the cached inverse", {
     expect_identical(x$getInverse(), im)
 })
 
+test_that("makeCacheMatrix(m)$set resets the cached inverse", {
+    x <- makeCacheMatrix()
+    
+    ## bogus inverse, just for unit testing
+    im <- matrix(1,1)
+    x$setInverse(im)
+    
+    m <- matrix(2,3)
+    x$set(m)
+
+    expect_identical(x$getInverse(), NULL)
+})
+
 test_that("cacheSolve(x) uses the cached inverse", {
     x <- makeCacheMatrix()
 

Original file line number	Diff line number	Diff line change
`@@ -11,7 +11,7 @@ makeCacheMatrix <- function(x = matrix()) {`
`11`	`11`	`## cached inverse`
`12`	`12`	`set <- function(y) {`
`13`	`13`	`x <<- y`
`14`		`- inv <- NULL`
	`14`	`+ inv <<- NULL`
`15`	`15`	`}`
`16`	`16`
`17`	`17`	`## Return the current matrix`