Merge pull request #142 from DavidRawk-Blake/allow_assert_called_at_l…

…east Added new function/macro to allow for "at_least" test
jjh42 · Jan 10, 2024 · 07081c1 · 07081c1
2 parents df4cc3d + 442accd
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diff --git a/README.md b/README.md
@@ -27,6 +27,7 @@ See the full [reference documentation](https://hexdocs.pm/mock/Mock.html).
 		* [Assert call order](#Assert-call-order)
 	* [Assert not called - assert a specific function was not called](#Assert-not-called---assert-a-specific-function-was-not-called)
 	* [Assert called exactly - assert a specific function was called exactly x times](#Assert-called-exactly---assert-a-specific-function-was-called-exactly-x-times)
+	* [Assert called at least - assert a specific function was called at least x times](#Assert-called-at-least---assert-a-specific-function-was-called-at-least-x-times)
 	* [NOT SUPPORTED - Mocking internal function calls](#NOT-SUPPORTED---Mocking-internal-function-calls)
 	* [Tips](#Tips)
 	* [Help](#Help)
@@ -418,6 +419,34 @@ defmodule MyTest do
 end
 ```
 
+## Assert called at least - assert a specific function was called at least x times
+
+`assert_called_at_least` will assert that a mocked function was called at least the expected number of times.
+
+```elixir
+defmodule MyTest do
+  use ExUnit.Case, async: false
+
+  import Mock
+
+  test "test_name" do
+    with_mock HTTPotion, [get: fn(_url) -> "<html></html>" end] do
+      HTTPotion.get("http://example.com")
+      HTTPotion.get("http://example.com")
+      HTTPotion.get("http://example.com")
+
+      # Using Wildcard
+      assert_called_at_least HTTPotion.get(:_), 2
+
+      # Using Specific Value
+      assert_called_at_least HTTPotion.get("http://example.com"), 2
+    end
+  end
+end
+```
+
+
+
 ### Assert call order
 
 `call_history` will return the `meck.history(Module)` allowing you assert on the order of the function invocation:

diff --git a/lib/mock.ex b/lib/mock.ex
@@ -220,6 +220,36 @@ defmodule Mock do
     end
   end
 
+  @doc """
+    Use inside a `with_mock` block to determine whether a mocked function was called
+    as expected at least x times. If the assertion fails, the number of calls that
+    were received is displayed in the assertion message.
+
+    Pass `:_` as a function argument for wildcard matches.
+
+    ## Example
+
+        assert_called_at_least HTTPotion.get("http://example.com"), 2
+
+        # Matches any invocation
+        assert_called_at_leaset HTTPotion.get(:_), 2
+  """
+  defmacro assert_called_at_least({{:., _, [module, f]}, _, args}, expected_times) do
+    quote do
+      unquoted_module = unquote(module)
+      unquoted_f = unquote(f)
+      unquoted_args = unquote(args)
+      unquoted_expected_times = unquote(expected_times)
+      actual_called_count = :meck.num_calls(unquoted_module, unquoted_f, unquoted_args)
+
+      if actual_called_count < unquoted_expected_times do
+        mfa_str = "#{unquoted_module}.#{unquoted_f}(#{unquoted_args |> Enum.map(&Kernel.inspect/1) |> Enum.join(", ")})"
+        raise ExUnit.AssertionError,
+          message: "Expected #{mfa_str} to be called at least #{unquoted_expected_times} time(s), but it was called (number of calls: #{actual_called_count})"
+      end
+    end
+  end
+
   @doc """
     Use inside a `with_mock` block to check if
     a mocked function was NOT called. If the assertion fails,

diff --git a/test/mock_test.exs b/test/mock_test.exs
@@ -127,6 +127,25 @@ defmodule MockTest do
     end
   end
 
+  test "assert_called_at_least" do
+    with_mock String, [reverse: fn(x) -> 2*x end] do
+      String.reverse(2)
+      String.reverse(2)
+      String.reverse(2)
+      assert_called_at_least(String.reverse(2), 3)
+      assert_called_at_least(String.reverse(2), 2)
+
+      try do
+        assert_called_at_least(String.reverse(2), 5)
+      rescue
+        error in [ExUnit.AssertionError] ->
+          """
+          Expected Elixir.String.reverse(2) to be called at least 5 time(s), but it was called (number of calls: 3)\
+          """ = error.message
+      end
+    end
+  end
+
   test "assert_not_called" do
     with_mock String,
       [reverse: fn(x) -> 2*x end] do