Merge pull request #93 from pgrange/time_delta

assert number equality within delta

Author: pgrange

README.adoc

@@ -106,6 +106,8 @@ Running tests in tests/test_core.sh
 	Running test_assert_status_code_fails ... SUCCESS
 	Running test_assert_status_code_succeeds ... SUCCESS
 	Running test_assert_succeeds ... SUCCESS
+	Running test_assert_within_delta_fails ... SUCCESS
+	Running test_assert_within_delta_succeeds ... SUCCESS
 	Running test_fail_fails ... SUCCESS
 	Running test_fail_prints_failure_message ... SUCCESS
 	Running test_fail_prints_where_is_error ... SUCCESS
@@ -147,6 +149,8 @@ Running tests in tests/test_core.sh
 	Running test_assert_status_code_fails ... SUCCESS
 	Running test_assert_status_code_succeeds ... SUCCESS
 	Running test_assert_succeeds ... SUCCESS
+	Running test_assert_within_delta_fails ... SUCCESS
+	Running test_assert_within_delta_succeeds ... SUCCESS
 	Running test_fail_fails ... SUCCESS
 Overall result: SUCCESS
 ```
@@ -178,6 +182,8 @@ ok - test_assert_shows_stdout_on_failure
 ok - test_assert_status_code_fails
 ok - test_assert_status_code_succeeds
 ok - test_assert_succeeds
+ok - test_assert_within_delta_fails
+ok - test_assert_within_delta_succeeds
 ok - test_fail_fails
 ok - test_fail_prints_failure_message
 ok - test_fail_prints_where_is_error
@@ -473,6 +479,35 @@ doc:2:test_obvious_matching_with_assert_not_matches()
 	Running test_obvious_notmatching_with_assert_not_matches ... SUCCESS
 ```
 
+=== *assert_within_delta*
+
+    assert_within_delta <expected num> <actual num> <max delta> [message]
+
+Asserts that the expected num matches the actual num up to a given max delta.
+This function only support integers.
+Given an expectation of 5 and a delta of 2 this would match 3, 4, 5, 6, and 7:
+
+```test
+test_matches_within_delta(){
+  assert_within_delta 5 3 2
+  assert_within_delta 5 4 2
+  assert_within_delta 5 5 2
+  assert_within_delta 5 6 2
+  assert_within_delta 5 7 2
+}
+test_does_not_match_within_delta(){
+  assert_within_delta 5 2 2
+}
+
+```
+
+```output
+	Running test_does_not_match_within_delta ... FAILURE
+ expected value [5] to match [2] with a maximum delta of [2]
+doc:9:test_does_not_match_within_delta()
+	Running test_matches_within_delta ... SUCCESS
+```
+
 === *assert_no_diff*
 
     assert_no_diff <expected> <actual> [message]

bash_unit

@@ -143,6 +143,32 @@ assert_not_matches() {
   fi
 }
 
+assert_within_delta() {
+  function abs() {
+    local value=$1
+    local sign=$(( value < 0 ? -1 : 1 ))
+    echo $((value * sign))
+  }
+  function is_number() {
+    local value=$1
+    test $value -eq $value 2>/dev/null
+  }
+  local expected=$1
+  local actual=$2
+  local max_delta=$3
+  assert "is_number $expected" "$message expected value [$expected] is not a number"
+  assert "is_number $actual" "$message actual value [$actual] is not a number"
+  assert "is_number $max_delta" "$message max_delta [$max_delta] is not a number"
+  local message=${4:-}
+  [[ -z $message ]] || message="$message\n"
+
+  local actual_delta="$(abs $(($expected - $actual)))"
+
+  if (( $actual_delta > $max_delta )); then
+    fail "$message expected value [$expected] to match [$actual] with a maximum delta of [$max_delta]"
+  fi
+}
+
 assert_no_diff() {
   local expected=$1
   local actual=$2

tests/test_core.sh

@@ -81,6 +81,36 @@ test_assert_not_equals_succeeds_when_not_equal() {
     'assert_not_equals should succeed'
 }
 
+test_assert_within_delta_succeeds() {
+  assert \
+    "assert_within_delta 12 10 3"\
+    'assert_within_delta should succeed'
+  assert \
+    "assert_within_delta 10 12 3"\
+    'assert_within_delta should succeed'
+  assert \
+    "assert_within_delta 10 12 2"\
+    'assert_within_delta should succeed'
+  assert \
+    "assert_within_delta 10 10 0"\
+    'assert_within_delta should succeed'
+}
+
+test_assert_within_delta_fails() {
+  assert_fails \
+    "assert_within_delta 13 10 2"\
+    'assert_within_delta should fail'
+  assert_fails \
+    "assert_within_delta 10 13 2"\
+    'assert_within_delta should fail'
+  assert_fails \
+    "assert_within_delta 11 10 0"\
+    'assert_within_delta should fail'
+  assert_fails \
+    "assert_within_delta eleven 10 0"\
+    'assert_within_delta should fail'
+}
+
 test_assert_no_diff_succeeds_when_no_diff() {
   assert \
     "assert_no_diff <(echo foo) <(echo foo)" \