[lmi-commits] [lmi] master 9cab906 2/3: Assert all documented preconditions; unit-test those assertions

[Greg Chicares]

branch: master
commit 9cab906839ebef8023e34e4d4e83bbd4f8c14839
Author: Gregory W. Chicares <address@hidden>
Commit: Gregory W. Chicares <address@hidden>

    Assert all documented preconditions; unit-test those assertions
---
 miscellany.cpp      |  7 +++----
 miscellany_test.cpp | 21 ++++++++++++++-------
 2 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/miscellany.cpp b/miscellany.cpp
index a0825af..54a4343 100644
--- a/miscellany.cpp
+++ b/miscellany.cpp
@@ -219,10 +219,9 @@ int page_count
     ,int rows_per_page
     )
 {
-    // The caller must check for this precondition because this function is too
-    // low-level to be able to handle it correctly, e.g. it can't even use the
-    // appropriate error message.
-    LMI_ASSERT(rows_per_group <= rows_per_page);
+    LMI_ASSERT(0 < total_rows);
+    LMI_ASSERT(0 < rows_per_group                 );
+    LMI_ASSERT(    rows_per_group <= rows_per_page);
 
     // Each group actually takes rows_per_group+1 rows because of the
     // separator row between groups, hence the second +1, but there is no
diff --git a/miscellany_test.cpp b/miscellany_test.cpp
index 7008ebc..8c483e5 100644
--- a/miscellany_test.cpp
+++ b/miscellany_test.cpp
@@ -170,18 +170,25 @@ void test_page_count()
 
     // Test preconditions.
 
-    // No data rows--doesn't actually throw.
-//    BOOST_TEST_THROW
-//        (page_count(0, 1, 1)
-//        ,std::runtime_error
-//        ,""
-//        );
+    // No data rows.
+    BOOST_TEST_THROW
+        (page_count(0, 1, 1)
+        ,std::runtime_error
+        ,lmi_test::what_regex("^Assertion.*failed")
+        );
+
+    // Zero rows per group.
+    BOOST_TEST_THROW
+        (page_count(1, 0, 1)
+        ,std::runtime_error
+        ,lmi_test::what_regex("^Assertion.*failed")
+        );
 
     // Insufficient room to print even one group.
     BOOST_TEST_THROW
         (page_count(1, 7, 3)
         ,std::runtime_error
-        ,""
+        ,lmi_test::what_regex("^Assertion.*failed")
         );
 
     // A single row of data.