diff --git a/src/lib.rs b/src/lib.rs
index 4eba336..b02b7d5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -776,7 +776,7 @@ impl Parser {
         let naive = self.build_naive(&res, &default_ts);
 
         if !ignoretz {
-            let offset = self.build_tzaware(&naive, &res, &default_ts)?;
+            let offset = self.build_tzaware(&naive, &res, tzinfos)?;
             Ok((naive, offset, tokens))
         } else {
             Ok((naive, None, tokens))
@@ -955,7 +955,7 @@ impl Parser {
         tzoffset: Option<i32>,
         token: &str,
     ) -> bool {
-        let all_ascii_upper = token == token.to_ascii_uppercase();
+        let all_ascii_upper = token.chars().all(|c| 65u8 as char <= c && c <= 90u8 as char);
         return hour.is_some() && tzname.is_none() && tzoffset.is_none() && token.len() <= 5
             && all_ascii_upper;
     }
@@ -1007,7 +1007,7 @@ impl Parser {
         &self,
         dt: &NaiveDateTime,
         res: &ParsingResult,
-        default: &NaiveDateTime,
+        tzinfos: HashMap<String, i32>,
     ) -> ParseResult<Option<FixedOffset>> {
         // TODO: Actual timezone support
         if let Some(offset) = res.tzoffset {
@@ -1017,6 +1017,12 @@ impl Parser {
                 || res.tzname == Some("-".to_owned()) || res.tzname == None)
         {
             Ok(None)
+        } else if res.tzname.is_some() && tzinfos.contains_key(res.tzname.as_ref().unwrap()) {
+            Ok(Some(FixedOffset::east(tzinfos.get(res.tzname.as_ref().unwrap()).unwrap().clone())))
+        } else if res.tzname.is_some() {
+            // TODO: Dateutil issues a warning/deprecation notice here. Should we force the issue?
+            println!("tzname {} identified but not understood. Ignoring for the time being, but behavior is subject to change.", res.tzname.as_ref().unwrap());
+            Ok(None)
         } else {
             Err(ParseError::TimezoneUnsupported)
         }
diff --git a/tests/compat.rs b/tests/compat.rs
index ea689b0..b572f8a 100644
--- a/tests/compat.rs
+++ b/tests/compat.rs
@@ -302,9 +302,9 @@ fn test_dateutil_compat() {
     // TODO: Uncomment tests once timezone support is in
 
     // testDateCommandFormat
-    // test_parse!(py, parser, datetime, "Thu Sep 25 10:36:28 BRST 2003");
+    test_parse!(py, parser, datetime, "Thu Sep 25 10:36:28 BRST 2003");
     // testDateCommandFormatReversed
-    // test_parse!(py, parser, datetime, "2003 10:36:28 BRST 25 Sep Thu");
+    test_parse!(py, parser, datetime, "2003 10:36:28 BRST 25 Sep Thu");
 
     // testDateCommandFormatStrip1
     test_parse!(py, parser, datetime, "Thu Sep 25 10:36:28 2003");
@@ -330,10 +330,9 @@ fn test_dateutil_compat() {
     test_parse!(py, parser, datetime, "2003");
     // testDateRCommandFormat
     test_parse!(py, parser, datetime, "Thu, 25 Sep 2003 10:49:41 -0300");
-    // testISOFormat
+    // testISOFormat - Needs some debug work on the python side
     // test_parse!(py, parser, datetime, "2003-09-25T10:49:41.5-03:00");
-    // TODO: tzoffset not properly recognized
-    // testISOFormatStrip1
+    // testISOFormatStrip1 - Needs same as above
     // test_parse!(py, parser, datetime, "2003-09-25T10:49:41-03:00");
     // testISOFormatStrip2
     test_parse!(py, parser, datetime, "2003-09-25T10:49:41");
@@ -499,22 +498,19 @@ fn test_dateutil_compat() {
 
     // testRandomFormat1
     test_parse!(py, parser, datetime, "Wed, July 10, '96");
-    // TODO: TZ support (PDT is unrecognized)
     // testRandomFormat2
-    // test_parse_ignoretz!(py, parser, datetime, "1996.07.10 AD at 15:08:56 PDT");
+    test_parse_ignoretz!(py, parser, datetime, "1996.07.10 AD at 15:08:56 PDT");
 
     // testRandomFormat3
     test_parse!(py, parser, datetime, "1996.July.10 AD 12:08 PM");
 
-    // TODO: UnrecognizedToken("PST")
     // testRandomFormat4
-    // test_parse_ignoretz!(py, parser, datetime, "Tuesday, April 12, 1952 AD 3:30:42pm PST");
-    // TODO: UnrecognizedToken("EST")
+    test_parse_ignoretz!(py, parser, datetime, "Tuesday, April 12, 1952 AD 3:30:42pm PST");
     // testRandomFormat5
-    // test_parse_ignoretz!(py, parser, datetime, "November 5, 1994, 8:15:30 am EST");
+    test_parse_ignoretz!(py, parser, datetime, "November 5, 1994, 8:15:30 am EST");
     // TODO: Parse error - finds hour 5 instead of 8
     // testRandomFormat6
-    // test_parse_ignoretz!(py, parser, datetime, "1994-11-05T08:15:30-05:00");
+    test_parse_ignoretz!(py, parser, datetime, "1994-11-05T08:15:30-05:00");
     // testRandomFormat7
     test_parse_ignoretz!(py, parser, datetime, "1994-11-05T08:15:30Z");
     // testRandomFormat8
@@ -533,22 +529,22 @@ fn test_dateutil_compat() {
     test_parse!(py, parser, datetime, "12h 01m02s am");
     // testRandomFormat15; NB: testRandomFormat16 is exactly the same
     test_parse!(py, parser, datetime, "0:01:02 on July 4, 1976");
-    // testRandomFormat17 - Needs ignoretz
+    // testRandomFormat17
     test_parse_ignoretz!(py, parser, datetime, "1976-07-04T00:01:02Z");
     // testRandomFormat18
     test_parse!(py, parser, datetime, "July 4, 1976 12:01:02 am");
     // testRandomFormat19
     test_parse!(py, parser, datetime, "Mon Jan  2 04:24:27 1995");
-    // testRandomFormat20 - Needs ignoretz
-    // test_parse_ignoretz!(py, parser, datetime, "Tue Apr 4 00:22:12 PDT 1995");
+    // testRandomFormat20
+    test_parse_ignoretz!(py, parser, datetime, "Tue Apr 4 00:22:12 PDT 1995");
     // testRandomFormat21
     test_parse!(py, parser, datetime, "04.04.95 00:22");
     // testRandomFormat22
     test_parse!(py, parser, datetime, "Jan 1 1999 11:23:34.578");
     // testRandomFormat23
     test_parse!(py, parser, datetime, "950404 122212");
-    // testRandomFormat24 - Needs ignoretz
-    // test_parse_ignoretz!(py, parser, datetime, "0:00 PM, PST");
+    // testRandomFormat24
+    test_parse_ignoretz!(py, parser, datetime, "0:00 PM, PST");
     // testRandomFormat25
     test_parse!(py, parser, datetime, "12:08 PM");
     // testRandomFormat26