First concept exercise, 4th task: compare JSON objects without ordered keys (#289)

[no important files changed]

Author: glennj

exercises/concept/shopping/bats-jq.bash

@@ -27,3 +27,64 @@ jq() {
     echo "$output"
     return "$rc"
 }
+
+#############################################################
+# These are extra assert functions for use in tests.
+
+# Assert two JSON objects are equal.
+#   https://jqlang.org/manual/v1.7/#==-!=
+#
+#   assert_objects_equal '{"a": 1, "b": 2}' '{"b":2,"a":1}' 
+#   # => true
+#
+assert_objects_equal() {
+    local result=$(
+        jq -n --argjson actual "$1" \
+              --argjson expected "$2" \
+            '$actual == $expected'
+    )
+    [[ $result == "true" ]]
+}
+
+# Assert 2 floating-point values are "close enough".
+#
+#   # are they the same to 2 decimal places?
+#   assert_float 1.993 1.995        # => true
+#
+#   # are they the same to 3 decimal places?
+#   assert_float -d 3 1.993 1.995   # => false
+#
+assert_float() {
+    local OPTIND OPTARG
+    local decimals=2 actual expected
+    while getopts :d: opt; do
+        case $opt in
+            d) decimals=$OPTARG ;;
+            *) return 2 ;;
+        esac
+    done
+    shift $((OPTIND - 1))
+    # bash can't do floating point: use awk
+    read -r actual expected < <(
+        awk -v d="$decimals" -v a="$1" -v e="$2" '
+            BEGIN {
+                m = 10 ^ d
+                print int(a * m)/m, int(e * m)/m
+            }
+        '
+    )
+    # now call a bats-assert command to get the desired output
+    assert_equal "$actual" "$expected"
+}
+
+# Assert that an object's value of a given key is the expected value.
+# This uses the bats `output` variable.
+#
+#   run jq -f ...
+#   assert_key_value 'the_key' 'the_expected_value'
+#
+assert_key_value() {
+    local key=$1 expected=$2 actual
+    actual=$(jq -rc --arg key "$key" '.[$key]' <<< "$output")
+    assert_equal "$actual" "$expected"
+}

exercises/concept/shopping/test-shopping.bats

@@ -27,5 +27,11 @@ load bats-jq
     ## task 4
     run jq -c -f shopping.jq shopping-list.json
     assert_success
-    assert_line --index 3 '{"buttermilk":"regular milk","melted butter":"vegetable oil","blueberries":"chopped apple"}'
+    assert_objects_equal \
+        "${lines[3]}" \
+        '{
+            "buttermilk":"regular milk",
+            "melted butter":"vegetable oil",
+            "blueberries":"chopped apple"
+         }'
 }

lib/bats-jq.bash

@@ -10,7 +10,6 @@
 # - "Printing to the terminal", https://bats-core.readthedocs.io/en/stable/writing-tests.html#printing-to-the-terminal
 # - "File descriptor 3", https://bats-core.readthedocs.io/en/stable/writing-tests.html#file-descriptor-3-read-this-if-bats-hangs
 
-
 jq() {
     local output stderr rc line
     stderr=$(mktemp)
@@ -27,3 +26,64 @@ jq() {
     echo "$output"
     return "$rc"
 }
+
+#############################################################
+# These are extra assert functions for use in tests.
+
+# Assert two JSON objects are equal.
+#   https://jqlang.org/manual/v1.7/#==-!=
+#
+#   assert_objects_equal '{"a": 1, "b": 2}' '{"b":2,"a":1}' 
+#   # => true
+#
+assert_objects_equal() {
+    local result=$(
+        jq -n --argjson actual "$1" \
+              --argjson expected "$2" \
+            '$actual == $expected'
+    )
+    [[ $result == "true" ]]
+}
+
+# Assert 2 floating-point values are "close enough".
+#
+#   # are they the same to 2 decimal places?
+#   assert_float 1.993 1.995        # => true
+#
+#   # are they the same to 3 decimal places?
+#   assert_float -d 3 1.993 1.995   # => false
+#
+assert_float() {
+    local OPTIND OPTARG
+    local decimals=2 actual expected
+    while getopts :d: opt; do
+        case $opt in
+            d) decimals=$OPTARG ;;
+            *) return 2 ;;
+        esac
+    done
+    shift $((OPTIND - 1))
+    # bash can't do floating point: use awk
+    read -r actual expected < <(
+        awk -v d="$decimals" -v a="$1" -v e="$2" '
+            BEGIN {
+                m = 10 ^ d
+                print int(a * m)/m, int(e * m)/m
+            }
+        '
+    )
+    # now call a bats-assert command to get the desired output
+    assert_equal "$actual" "$expected"
+}
+
+# Assert that an object's value of a given key is the expected value.
+# This uses the bats `output` variable.
+#
+#   run jq -f ...
+#   assert_key_value 'the_key' 'the_expected_value'
+#
+assert_key_value() {
+    local key=$1 expected=$2 actual
+    actual=$(jq -rc --arg key "$key" '.[$key]' <<< "$output")
+    assert_equal "$actual" "$expected"
+}